6-acyl derivatives of amino-penicillanic acid

ABSTRACT

COMPOUNDS REPRESENTED BY THE FOLLOWING FORMULA, A PROCESS FOR THEIR PREPARATION AND NOVEL INTERMEDIATES THEREFOR ARE DISCLOSED. THESE COMPOUNDS ARE USEFUL ANTIBIOTICS.   2-(HOOC-),3,3-DI(CH3-),6-(R-COO-CH(-T)-CO-NH-)PENAM   WHEREIN R IS A SUBSTITUTED PHENYL RADICAL AND T IS A C2C5 ALKYL OR ALKENYL, A CYCLOPROPYLMETHYL OR CYCLOBUTYLMETHYL, OR AN ARLAKYL CONTAINING UP TO 8 CARBON ATOMS.

United States Patent U.S. Cl. 260-2391 16 Claims ABSTRACT on THEDISCLQSURE Compounds represented by the following formula, a process fortheir preparation and novel intermediates therefor are disclosed. Thesecompounds are useful anti biotics. Y

wherein R is a substituted phenyl radical and T is a C C alkyl oralkenyl, a cyclopropylmethyl or cyclobutylmethyl, or an aralkylcontaining up to 8 carbon atoms.

RELATED APPLICATION This application is a continuation-in-part of US.patent application Ser. No. 160,564, filed July 7, 1971, now abandoned.

DETAILED DESCRIPTION OF THE DISCLOSURE The present invention is directedto novel 6-acylaminopenicillanic acid compounds represented by thegeneral formula (X). T V O=CNCH 0013'. (I) wherein X ishydrogen,halogen, C 0 alkyl, C -C alkoxy, C -C alkylthio, (C -C4alkanoyloxy)-methyl, (C -C alkoxy)-methyl, C C -alkoxy-acetamido, hy-

droxy-(C -C alkyl), amino-(C C aIkyl), di-(C -C alkyl)-amino, C -Calkyl-sulfonamido, 0 -0, alkylsulfonyl, sulfamoyl, carbamoyl, amino,nitro, phenyl, trifiuoromethyl, cyano, pyrrol-l-yl or hydroxy or two Xsymbols on adjacent carbon atoms together are a C -C alkylenedioxy; n isa whole number from 1 to 3 and T is a C -C alkyl, a C -C alkenyl, acyclopropylmethyl, a cyclobutylmethyl or an aralkyl containing up to 8carbon atoms, and pharmaceutically acceptable salts and hydrated formsthereof.

The invention is also directed to the preparation of the compounds ofFormula I utilizing the novel intermediate compounds represented by theformula Q-oooon-ooorr (X). wherein X, n and T have the meanings givenabove fluorine, chlorine and bromine. Where X in Formulas I and IIrepresents a fluorine atom, n preferably is 1 and where X is bromine, npreferably is 1 or 2.

In accordance with the present invention, alkyls represented by X inFormulas I and II are methyl, ethyl, n propyl and isopropyl. In general,methyl is preferred.

- Alkyls or alkenyls represented by T in Formulas I and II may bestraightor branched-chain. Examples of such substituents include ethyl,n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl and 3-methylbutyl,vinyl, allyl, methallyl, butenyl and pentenyl. Examples of aralkylsrepresented by T in Formulas I and II are benzyl and phenethyl.

Preferred compounds in accordance with the present invention are thosecompounds of Formulas I and II wherein n is 1 or 2 and the substituent Xis in the 3- and/or 4-position. In these preferred compounds, X isselected from the group consisting of chlorine, bromine or methoxy and Tis alkyl or a C -C alkenyl, especially isobutyl or cyclopropylmethyl.Especially preferred penicillin compounds in accordance with the presentinvention are set forth in the following table of results of activityscreening against various organisms. In the table, the antimicrobialactivity of the compounds tested is expressed in terms of the minimalinhibitory concentration in mg./ml. The minimal inhibitory concentrationwas determined by double dilution series in nutrient bouillon.

TABLE [Minimal Inhibitory Concentration, mg./m1.]

In vitro In vivo 8. E. S. E. aureua colt aureua col Compound FDA 1346FDA 1346 R) -1-(4-chlorobenzoxyloxy)-3- methylbutyil-penicillinsodium.-- 0. 16 19 2. 3 31. 5 [(R) -1-(3 4-dichiorobenzoyloxy)-3-methylbutyl]-penicillin sodium-.. 0. 16 3. 0 48 [(R,S)-1-(4-ch1orobenzoy1oxy)-3- methyibutyll-penicillin sodium 0. 3 5 5 57[(R, S) -1-(p-fiuorobenzoyloxy)-3- methylbutyH-penicillin potasu.u1 0. 619. 5 25 47 [(R.S)-1-(3-bromobenzoyloxy)- pentyH-penicillin 0. 16 5 0. 951 [(R,S)-1-(2-chlorobenzoyloxy)- pentyl]-penicil1in potassium 0. 1610 1. 5 61 [(R)-1-(4-methoxymethyl-beuzoyloxy)-3-methylbutyl]penicillinsodium 0. 04 19 12 12 (R)-1-(4-acetoxymethyl-benzoyloxy)-3-methylbutyl]-penicillin sodium 0. 0419 6 18 [(R) 3-methyl-1-(4-phenylbenzoyloxy)-buty1]-penici11in sodium0.3 19.5 1.8 27 [(R) -1-(p-anisoy1oxy)-3-methoxyhutylI-peniciiiin sodium0. 3 1. 25 3 47 [(R)-3-methyl-1-(3,4 5-trimethoxy- 0. 6 1. 25 10. 8 47benzoyloxy)-butyl -penicil1in i3 i tr'ii' ""=t"b '1'"? -me y p-m roenzoy oxy butylI-penicillin sodium 0. 15 1. 25 2. 6 12[(R)-3-methyl-l-(p-methylthiobenzoyloxy)-butyl]-penicillin sodium; 0.160. 62 1.8

Especially preferred among the acid starting compounds of Formula II arethose which give rise to the penicillin compounds listed in the abovetable.

In accordance with the present invention, the compounds of Formula I areprepared by condensing 6- aminopencillanic acid, the carboxyl of whichis in a protected form, with the novel compounds of Formula II or afunctional derivative thereof. Such functional derivatives include, forexample, halides, azides, anhydrides, reactive esters such as theN-hydroxysuccinimide esters, amides such as imidazolides and the like.The acids of Formula H wherein X is a strongly basic group have suchgroup in a protected form. After the reaction is completed, theprotecting group(s) is cleaved 01f and, if desired, the product isconverted into a salt.

Examples of methods whereby the carboxyl ofG-aminopenicillanic acid canbe protected include conversion into a readily cleavable ester such as,for example, the benzyl ester, a p-bromophenacyl esteror a silyl estersuch as the trimethyl silyl ester or by salt formation with an inknownin the art. For example, a p-bromophenacylester group can be cleaved bymeansv of treatment with potassium thiophenolate, a silyl ester canreadily be removed with water, as is well known in the art. I v

Examples of methods whereby substituents represented by X in Formula IIwhich are more basic than, for-example, H N--CH,-, may be protectedprior to the condensation reaction include formation of theo-nitrophenylsulfenyl group via the corresponding chlorides, as is knownin the art. This readily cleavable protecting group can be removed afterthe condensation reaction by treatment; with thioacetamide at a pH of2.5 to 3 and a temperatureof between "-l C. and C.

.The condensation of 6-aminopenicillanic acid having a protectedcarboxyl and the compound of Formula II is carried out by methods wellknown in the art of peptide chemistry. Thus, for example, thecondensation is effected in the presence of a carbodiimide such asdicyclohexylcarbodiimide or an oxazolium salt such as N-ethyl-S-phenyl-isoxazolium-3'-sulfonate in an inert solvent. Suitable solventsinclude, for example, ethyl acetate, acetonitrile dioxan, chloroform,methylene chloride, benzene, dimethylformamide and the like. In a likemanner, a salt of a G-aminopenicillanic acid such as, for example, atrialkylammonium salt is condensed with a reactive functional derivativeof a compound of Formula II.

The compounds of Formula II may be utilized in an optically uniform formor as racemates. Insofar asthey are not known or described hereinafter,such compounds can be prepared in analogy to the procedures set forth inthe following examples for individual compounds. For example, anoptically active or racemic compound represented by the general formulacan be reacted with a reactive acid derivative such as, for example, ananhydride or halide, for a compound represented by the general formulawherein X and n have the meanings given to yield a compound of FormulaII. I 1 I An alternate method for the preparation of the compounds ofFormula II comprises converting an optically active or racemic compoundof Formula III into a readily cleavable ester such as, for example, thebenzyl ester or the t-butyl ester, and reacting this ester with a reactive acid derivative of a compound of Formula IV in the presence of abase such as, for example, sodium hydrogen carbonate, pyridine,triethylamine and the like. The ester group is then removed, forexample, by hydrogenolysis in the case of the benzyl ester or mild acidhydrolysis in the case of the t-butyl ester.

Another method for the preparation of the com'- pounds of Formula IIcomprises reacting a readily leav able ester of an optically active orracemic compound represented by the general formula 7 wherein -Y-.is ahalogen-and-T has .therneaning-given 1:

with an alkali metal or alkaline earth metal salt of a compound ofFormula IV or with a compound of the Formula IV in the presence ofatertiary nitrogen-containing base such as, .for example, tr'iethylaminein an inert solvent. The readily ,cleayable protecting' ester group isthereafter removedfas described above 1 The 6-acyl derivatives offi-aminopenicillanic acid pro vided by the present invention possess abroad spectrum of activity against both Gram-positive such as tS t aphyloc0 ccus aureus, Diplococcus pneumoniae and Streptococcm pyogenes andGram-negative microorganisms such as. Escherichia coli', Proteusvulgaris, Proteus mirabilis and Salmonella typhimurt'um T heirantibiotic and bactericidal, activity allows them to'be utilizedtherapeutically and asdisinfectants. It is preferred i n accordance withthe invention to administer the novel penicillin compounds describedherein orally in view of their superior stability against gastric acid.It is contemplated in the case of adults, oral'dosage forms containingZOO-600mg. are administered three or four times daily.- This dosageregimen may be adjusted by the clinicianasthe therapeutic;

situation requires. The novel penicillin compounds of.t hef inventionmay also be administered parenterally, rectally. or topically insuitable dosage forms and may be administered in the form of theirpharmaceutically acceptable salts or hydrates.

Examples of the pharmaceutically acceptable salts of the penicillincompounds of Formula I include salts with inorganic bases such as, forexample, the alkali metal salts, for example, the sodium or "potassiumsalt, am? monium' salts, alkaline earth metal salts such as, for example, the calcium salt and the like and salts with'or ganie bases suchas amine compounds, for example, N- ethyl piperidine, procaine,dibenzylamine, N,N'-dibenzylethylethylenediamine, alkylamines,dialkylamines or the like. These salts 'can' alsobe hydrated.Thehydration can be efiected during the manufacturing process or canoccur gradually as a consequence of the hygroscopic properties" of aninitially anhydroussalt.

The compounds of Formula I and their salts can exist as optically pureisomers and as diastereo'menmixtures.

For purposes of administrationfthe novel-l6-acyl' derivatives ofG-aminopenicillanic acid of the present in- 'vention can be combinedwith conventional compatible organic or inorganic pharmaceutical carriermaterials known in the art. Such materials include, for example, water,gelatin, gums, lactose, starches, magnesium stearate, talc, vegetableoils, polyalkylene glycols, petroleum jelly and .the like. Such'pharmaeeuticalpreparations may be in unit dosage form and mayadditionally contain other therapeutically valuable substances orconventional pharmaceutical adjuvants such-as preservatives,

stabilizing agents, wetting. agents, emulsifying agents, buffers and thelike. The pharmaceutical preparations can be in conventional soliddosage forms such-as tablets, capsules, dragesa-iandtthe like,conventional semisolid forms such as ointments and creams, conventionalliquid forms suchas solutions, suspensions, emulsions andthe like andother conventional dosage forms such as dry ampules, suppositories andthe like. Such preparations may be submitted to conventionalpharmaceutical expedients such as, for example, sterilization and thelike. v

The following examples illustrate the process provided by the presentinvention. All temperatures are in degrees centigrade.

EXAMPLE 1 chloride was then added dropwise thereto with stirring. Thereaction mixture was stirred for three hours at -l and then allowed tostand for 20 hours at 25. .The pyridine was distilled off in a vacuum at50. After ice had been added, the residue was made congoacidic with 3 Nhydrochloric acid and extracted with 250 ml. of ethyl acetate. The ethylacetate phase was washed twice with 1 N hydrochloric acid and twice withwater, dried with magnesium sulphate and evaporated in a vacuum at 40.The residue was then suspended in 70 ml. of benzene, the insolublep-chlor'obenzoic acid filtered off and the filtrate evaporated in avacuum. The resin thus obtained was dissolved in petroleum ether and thesolution stored at 0 for 3 hours, filtered off from a further amount of4-chlorobenzoic acid, evaporated in a vacuum, at 40 and the residuedried. R-e-(4-chlorobenzoyloxy)- isocaproic acid was thus obtained as aviscous oil. [m] =+8.O (c.=4.3 in alcohol).

15.7 g. of the foregoing acid were dissolved in 50 ml. of absolutebenzene, treated with 10 ml. of thionyl chloride and heated to 70 for 45minutes. The solution was then evaporated in a vacuum at 45, theresulting syrup evaporated twice with 30 ml. portions of benzene and theR-a-(4-chlorobenzoyloxy)-isocaproic acid chloride dried in a vacuum at45. The acid chloride was used in this form in the process as follows.

(B) The process:

A solution of 2.9 g. of R-u-(4-chlorobenzoyloxy)-isocaproic acidchloride formed above in 15 ml. of methylene chloride was added dropwisewith stirring to a solution of 2.3 g. of 6-aminopenicillanic acid in amixture of 25 ml. of methylene chloride and 2.8 m1. of triethylaminewhich had been cooled to -15". The mixture was maintained at 0 for 20hours and then evaporated in a vacuum at 20. The residue was dissolvedin 30' ml. of ice-water and extracted twice with 15 ml. of ether. Theaqueous phase was adjusted to pH 2 at 0 with 3 N sulphuric acid andextracted three times with 30 ml. portions of ether. The ether solutionswere washed three times with 10 ml. portions of ice-water, dried withmagnesium sulphate and evaporated in a vacuum at 20. The[(R)-1-(4-chlorobenzoyloxy) 3-methylbutyl]-penicillin thus obtained wassuspended in 20 ml. of water at The pHof the suspension was thenadjusted to pH 7 with sodium bicarbonate solution and the wholefiltered. The filtrate was evaporated to dryness in 'a vacuum at 20.There was obtained [(R)-1-(4-chlorobenzoyloxy) -3-methtylbutyl]-penicillin sodium which. was dissolved in 15 ml. of ethyl acetate. Thesolution was filtered and treated with 150 ml. of low-boiling petroleumether. The precipitated sodium salt was separatedofi, washed withlow-boiling petroleum ether, dried and recrystallized from ethylacetate. Melting point=21l (decomposition); [u] =+202 (c.=0.5 in water).

EXAMPLE 2 (S) -l-(4 -chlorobenzoyloxy)-3-methylbutyl]- v penicillinsodium (A) The preparation of the starting material:

23.5 g. of 4-chlorobenzoyl chloride were added drop-J wise with stirringover a period of 20 minutes to'a solution of 20.0 g. of 4-chlorobenzoicacid in 160 ml. of tetrahydrofuran and 18 ml. of triethylamine which hadbeen cooled to 30. The mixture was stirred at 30 for 30 minutes and thena solution of 16.9 g. of (S)-ozhydroxy-isocaproic acid and 18 ml. oftriethylamine in 60 ml. of tetrahydrofuran was added dropwise. Thereaction mixture was then stirred at 3-0 for 3 hours and at 20 to 25 for12 hours. The insoluble precipitate was sepa rated oil and the filtrateevaporated in a vacuum at The resulting syrup was dissolved in 300 ml.of ethyl acetate, made congo-acidic at 0 with 3 N hydrochloric acid andthe insoluble 4-chlorobenzoic acid filtered" off in a vacuum. The ethylacetate solution was 'thenfseparated off, washed three times with 40 ml.of water, dried with magnesium sulphate and evaporated in a vacuum at40. The residue was suspended in 40ml. of benzene, the insoluble4-chlorobenzoic acid separated 011? and the filtrate evaporated in avacuum at 40. The resulting syrup was dissolved in 40 ml. of low-boilingpetroleum ether, maintained at 25 for 4 hours and thereafter the4-chlorobenzoic acid which again crystallizes out was filtered off. Thefiltrate was evaporated and dried in a vacuum,"to yield(S)-a-(4-chlorobenzoyloxy)-isocaproic acid as a viscous oil. [a] =8.0(c. =4.3 in alcohol).

If the R form is desired, the acid can be converted into the acidchloride as described in Example 1(A).

(B) The process:

By following the procedure described in Example 1(B), from(S)-a-(4-chlorobenzoyloxy)-isocaproic acid there was obtained[(S)-1-(4-chlorobenzoyloxy)-3-methylbutyl]-penicillin sodium; [a]=+160i5 (c.'=0.5 in water).

- EXAMPLE 3 (R) 1-(3,4-dichlorobenzoyloxy) -3-methyl-butyl]- penicillinsodium (A) The preparation of the starting material:

17.5 g. of 3,4-dichlorobenzoyl chloride were added dropwise over aperiod of 20 minutes to a cold (15) solution of 10.0 g. ofR-a-hydroxy-isocaproic acid in 60 ml. of pyridine. The mixture wasstirred at -10 for 3 hours and at 25 for 20 hours. The pyridine wasdistilled oif ina vacuum at 50. Ice was added and the residue madecongo-acidic with 3 N hydrochloric acid and extracted with 200 ml. ofethyl acetate. The ethyl acetate phase was washed twice with 50 ml. of lN hydrochloric acid and twice with 50 ml. of water, dried with magnesiumsulphate and evaporated in a vacuum at 40. The residue was suspended'in150 ml. of low-boiling petroleum ether. The insoluble3,4-dichlorobermoic acid was filtered off, the filtrate evaporated in avacuum at 40, the resulting syrup dissolved in 50 ml. of low-boilingpetroleum ether and maintained at 25 for 3 hours. The mixture was thenfiltered off from a small amount of 3,4-dichl orobenzoic acid and thefiltrate evaporated in a vacuumat 40 The oilyR-ot-(3,4-dichlorobenzoylox isocaproic acid was dried'in ayacuum at 40and c Iii verted into R-a- ('3,4-dichlorobenz'oyloxy) isocaproic acidchloride with thionyl chloride. p

(B) The process; j p i r A solution of 3.2 g. ofR-ir-(3,4-dichlorobenzoyloxy) isocaproic acid chloride formed above in15 inl. offmeth ylene chloride, was added dropwise with stirring to asolution of 2.3 g. 'of 6-aminopenicillanic acid in "ajmix ture of 25 ml.of methylene, chloride and 2.8 ml. of hiethylamine which hadbeencooledto 40.. The mixture was maintained at 0 for 20 hours.Thefsol'vent was dis-f, tilled oif in a vacuum at 20 and the residue"dissolved in 30 ml. of ice-water. The aqueous solution was thenextracted twige'with 10 ml. portions of ether adjusted to. pH 2 atwith.3 N sulfuric acid and extracted .3 times with 30 ml. portions ofether-leach time. The ether extracts were then washed 3 times with 15ml. portions of 7 EXAMPLE 4 I (R,S)-l-(4-chlorobenzoyloxy)-propyl1-penicillin potassium (A) The preparation of the starting material:

A solution of 31.3 g. of 4-chlorobenzoic acid, 51.4 g. ofR,S-a-bromobutyric acid benzyl ester and 22.3 g. of triethylamine in 400ml. of absolute dioxan was boiled under reflux for 20 hours. Aftercooling, the triethylamine hydrobromide which crystallized out wasfiltered oil by suction. The filtrate was then evaporated in a vacuumand the residue taken up in 500 ml. of ethyl acetate. The ethyl acetatesolution was washed with Water, ice-cold 5 percent sodium bicarbonatesolution and water, dried over magnesium sulphate and evaporated in avacuum. The residual R,S-m-(4-chlorobenzoyloxy)-butyric acid benzylester was distilled in a high vacuum. Boiling point 143-145/0.05 mm. Hg.

33 g. of R,S-a-(4-chlorobenzoyloxy)-butyric acid benzyl ester weredissolved in 700 ml. of alcohol and, with the addition of 'Pd/ C,hydrogenated up to the uptake of the theoretical amount of hydrogen. Thecatalyst was separated off, the filtrate evaporated in a vacuum and theresidue dissolved in 500 ml. of ethyl acetate. The ethyl acetatesolution was washed with water and extracted twice with 150 ml. portionsof 5 percent sodium bicarbonate solution. The alkaline solution wascooled with ice, made congo-acidic with concentrated hydrochloric acidand extracted with 450 ml. of ethyl acetate. The ethyl acetate solutionwas washed with water, dried over magnesium sulphate and evaporated in avacuum. The R,S-a-(4-ch1orobenzoyloxy)-butyric acid thus obtained wasrecrystallized from cyclohexane. Melting point 81- 82.

(B) The process:

A solution of 12.1 g. of R,S-a-(4-chlorobenzoyloxy)- butyric acid in 100ml. of absolute chloroform, cooled to l5 was treated with 5.1 g. oftriethylamine and 6.0 g. of pivaloyl chloride and the mixturesubsequently stirred at for 30 minutes. A solution of 10.8 g. of6-aminopenicillanic acid and 10.1 g. of triethylamine in 100 ml. ofabsolute chloroform which had been cooled to -40 was then added. Thesolution was stirred at 10 for 3 hours and allowed to stand at 4 for 70hours. The solvent was then removed in a vacuum and the residuedissolved in 200 m1. of ice-water. The solution was extracted with two100 ml. portions of ether, cooled to 2 adjusted to pH 2.1 with 1, Nhydrochloric acid and then extracted with two 250 ml. portions of ethylacetate. The ethyl acetate solution was washed with two 250 ml. portionsof water, dried over magnesium sulphate, concentrated to ca. 100 ml. ina vacuum and treated with 800 ml. of low-boiling petroleum ether. Theprecipitated [(R,S) l (4-chlorobenzoyloxy)-propyl]- penicillin was againreprecipitated from ethyl acetate and low-boiling petroleum ether, driedand dissolved in 200 ml. of absolute ether. With stirring andice-cooling, the solution was treated with 100 ml. of absolute etherwhich contained 25 ml. of a 2 M solution of potassium 2-ethylcaproate inisopropanol. After the addition of 600 ml. of low-boiling petroleumether, the precipitated [(R,S)-l-(4-chlorobenzoyloxy)-propyl]-penicillin potassium was filtered off bysuction, washed with low-boiling petroleum ether and dried. Meltingpoint 176177 (decomposition); [a] =-+196 (c.=1 in water).

EXAMPLE 5 [(R,S)-1-(3-chlorobenzoyloxy)-propyl]-penicillin potassium (A)The preparation of the starting material:

A solution of 31.3 g. of 3-ehlorobenzoic acid, 51.4 g. ofR,S-bromobutyric acid benzyl ester and 22.3 g. of triethylamine in 400ml. of absolute dioxan was boiled under reflux for hours. After cooling,the triethylamine hydrobromine was filtered oif by suction and thefiltrate evaporated in a vacuum. The residue was taken up in 500 ml. ofethyl acetate. The ethyl acetate solution was washed with water,ice-cold 5 percent sodium sulphate and evaporated in a vacuum. Theresidual R,S-a-(3- chlorobenzoyloxy)-butyric acid benzyl ester wasdistilled in a high vacuum. Boiling point 143 145/ 0.01 mm. Hg.

29.6 g. of -R,S-a-(3-chlorobenzoyloxy)-butyric acid benzyl ester weredissolved in 650 ml. of alcohol and, with the addition of Pd/C,hydrogenated up to the uptake of the theoretical amount of hydrogen. Thecatalyst was then separated oil, the filtrate evaporated in a vacuum andthe residue dissolved in 500 ml. of ethyl acetate. The ethyl acetatesolution was washed with water and extracted twice with 150 ml. portionsof a 5 percent sodium bicarbonate solution. The alkaline solution wascooled with ice, made congo-acidic with concentrated bydrochloric acidand extracted with 450 m1. of ethyl acetate. The ethyl acetate solutionwas washed with water, dried over magnesium sulphate and evaporated in avacuum. The R,S-a-(3 chlorobenzoyloxy)-butric acid thus obtained wasrecrystallized from cyclohexane. Melting point -81.

(B) The process:

A solution of 10.7 g. of R,S-a-(3-chlorobenzoyloxy)- butyric acid in ml.of absolute chloroform, cooled to 15, was treated with 4.5 g. oftriethylamine and 5.3 g. of pivaloyl chloride and the mixture stirred at15 for 30 minutes. A solution of 9.5 g. of 6-aminopencillanic acid and8.9 g. of triethylamine in 100 m1. of absolute chloroform, cooled to 40,was then added to the mixture. The solution was stirred at 10 for 3hours and left to stand at 4 for 70 hours. The solvent was evaporatedofi in a vacuum and the residue dissolved in 200 ml. of ice-water. Theaqueous solution was extracted with two 100 ml. portions of ether,cooled to 2, adjusted to pH 2.1 with 1 N hydrochloric acid and extractedwith two 250 ml. portions of ethyl acetate. The ethyl acetate solutionwas washed with two 250 ml. portions of water, dried over magnesiumsulphate, concentrated to ca. 100 ml. in a vacuum and treated with 800ml. of low-boiling petroleum ether. The precipitated[(R,S)-I-(3-chlorobenzoyloxy)-propyl]-penicillin was reprecipitated fromethyl acetate and low-boiling petroleum ether, dried and dissolved in200 ml. of absolute ether. With stirring and ice-cooling, the solutionwas treated with 100 ml. of absolute ether which contained 22 ml. of a 2M solution of potassium 2-ethyl-caproate in isopropanol. After the IEXAMPLE 6 [(R,S) 1- 3 ,4,-dichlorobenzoyloxy) -propyl] penicillinpotassium (A) The preparation of the starting material:

A solution of 38.4 g. of 3,4-dichlorobenzoic acid, 51.4 g. ofR,S-a-'bromobutyric acid benzyl ester and 22.3 g. of triethylamine in400 ml. of absolute dioxane was boiled under reflux for 20 hours. Aftercooling, the triethylamine hydrobromide was filtered otf by suction andthe filtrate evaporated in a vacuum. The residue was then taken up in500 ml. of ethyl acetate. The ethyl acetate solution was washed withwater, ice-co1d 5 percent sodium bicarbonate solution and water, driedover magnesium sulphate and evaporated in a vacuum. The residualR,S-a-(3,4dichlorobenzoyloxy)-butyric acid benzyl ester was distilled ina high vacuum. Boiling point 151-152 /0.01 mm. Hg.

32.8 g. of R,S-a-(3,4-dichlorobenzoyloxy)-butyric acid benzyl ester weredissolved in 650 ml. of alcohol and, with the addition of Pd/C,hydrogenated up to the uptake of the theoretical amount of hydrogen. Thecatalyst was then separated off, the filtrate evaporated in a vacuum andthe residue dissolved in 500 ml. of ethyl acetate. The ethyl acetatesolution was washed with water and extracted twice with 150 n11.portions of percent sodium bicarbonate solution. The alkaline solutionwas cooled with ice, made congo-acidic with concentrated hydrochloricacid and extracted with 450ml. of ethyl acetate. The ethyl acetatesolution was washed with water, dried over magnesium sulphate andevaporated in a vacuum. The R,S-a-(3,4-dichlorobenzoyloxy)-butyric acidthus ob tained is recrystallized from cyclohexane. Melting point121-l22.

(B) The process:

A solution of 13.9 g. of 'R,S-a-(3,4-dich1orobenzoyloxy)-butyric acid in100 ml. of absolute chloroform which had been cooled to 15 was treatedwith 5.1 g. of triethylamine and 6.0 g. of pivaloyl chloride and themixture is stirred at -15 for 30 minutes. A solution of 10.8 g. of6-aminopenicillanic acid and 10.1 g. of triethylamine in 100 ml. ofabsolute chloroform, cooled to- 40, was then added to the mixture. Thesolution was stirred at l0 for 3 hours and left to stand at 4 for 70hours. The solvent was evaporated off in a vacuum and the residuedissolved in 200 ml. of ice-water. The aqueous solution was extractedwith two 100 ml. portions of ether, cooled to 2 adjusted to pH 2.0 with1 N hydrochloric acid and extracted with two 300 ml. portions of ethylacetate. The ethyl acetate solution was Washed with two 250 ml. portionsof water, dried over magnesium sulphate, concentrated to ca. 100 ml. ina vacuum and treated with 800 ml. of low-boiling petroleum ether. Theprecipitated (R,S)-1-(3,4-dichlorobenzoyloxy) propyl] penicillin wasreprecipitated from ethyl acetate and low-boiling petroleum ether, driedand dissolved in 150 ml. of absolute ether. The solution is filteredand, with stirring and icecooling, treated with 100 ml. of absoluteether which contained 25 ml. of a 2 M solution of potassium2-ethylcaproate in isopropanol. After the addition of 700 ml. oflow-boiling petroleum ether, the precipitated [(R,S)-1-(3,4-dichlorobenzoyloxy)-propyl] penicillin potassium was filtered oil bysuction, washed with low-boiling petroleum ether and dried. Meltingpoint 180 (decomposition); [111 +155 (c.=1 in water).

EXAMPLE 7 (R,S) -1- 4-chlor0benzoyloxy) -3 -methylbutyl] penicillinsodium (A) The preparation of the starting material:

100.0 g. of R,S-u-bromo-isocaproic acid, 75 ml. of benzyl alcohol, 1.0g. of p-toluenesulphonic acid hydrate and 600 ml. of absolute toluenewere boiled under reflux for 6 hours under a water-separator. The cooledsolution was Washed with potassium bicarbonate solution and with water,dried over magnesium sulphate and evaporated in a water-jet vacuum. Inorder to remove excess benzyl alcohol, the residue was distilled for afurther 1 hour in a rotary evaporator at 0.1 torr and 70bath-temperature under a Co /acetone condenser. There was obtained 145g. of R,S-a-bromo-isocaproic acid benzyl ester l (n =1.5l32) which wasnot distillable at 0.1 torr and 70. The benzyl ester is processedwithout further purification.

The 145 g. of R,S-u-'bromo-isocaproic acid benzyl ester thus obtained in1 litre of dimethylformamide were treated portionwise with stirring andgassing with nitrogen with 126.0 g. of the sodium salt of4-chlorobenzoic acid and the mixture subsequently heated to 120 withstirring for 2 hours. After cooling, the mixture was poured on to anice-water mixture and extracted with high-boiling petroleum ether. Thepetroleum ether phases were washed with water, dilute sodium bicarbonatesolution and water, dried over magnesium sulphate, strongly concentratedin a vacuum and dried at 0.1 torr at 60. There was obtained 174 g. ofcrude R,S cc (4-chlorobenzoyloxy)-isocaproic acid benzyl ester.

The 174 g. of crude R,S-a-(4-chlorobenzoyloxy)-isoeaproic acid benzylester thus obtained were, after the addition of 3.0 g. of 5%palladium-charcoal, hydrogenated in 800 ml. of absolute alcohol. Afterthe uptake of 10.1 litres of hydrogen, the catalyst was filtered off andthe filtrate evaporated in a vacuum. The residue was dissolved withheating in 300 ml. of high-boiling petroleum ether, filtered andcrystallized at 0. There Was obtained 107 g. ofR,S-a-(4-chlorobenzoyloxy)-isocaproic acid of melting point 9798.

15 g. of the R,S-u-( l-chlorobenzoyloxy)-isocaproic acid thus obtainedwere heated in 45 ml. of benzene for 3 hours with 12 ml. of thionylchloride, evaporated, evaporated three times with 30 ml. portions ofbenzene in a vacuum at 35 and dried. There was obtained 16 g. ofR,-S-oz-(4 chlorobenzoyloxy) isocaproic acid chloride which is used inthe process in crude form.

(B) The process:

In analogy to the procedure described in Example 1(B), from6-arninopencillanic acid and R,S-a-(4-chlorobenzoyloxy)-isocaproic acidthere was obtained [(R,S)-l-(4- chlorobenzoyloxy)-3 methylbutyl]pencillin sodium; [a] =+162.5 (c.-=0.5 in water).

EXAMPLE 8 (R,S -1-(benzoyloxy)-propyl]-penicillin potassium (A) Thepreparation of the starting material:

A solution of 12.2 g. of benzoic acid, 25.7 g. of R,S-abromobutyric acidbenzyl ester and 1.1 g. of triethylamine in 200 ml. of absolute dioxanWas boiled under reflux for 20 hours. After cooling, the triethylaminehydrobromide was filtered 01f by suction and the filtrate evaporated ina vacuum. The residue was then taken up in 300 ml. of ethyl acetate. Theethyl acetate solution was washed with water, ice-cold 5 percent sodiumbicarbonate solution and water, dried over magnesium sulphate andevaporated in a vacuum. The residual R,Sa-benzyloxy-butyric acid benzylester was distilled in a high vacuum. Boiling point 120 122/0.01 mm. Hg.

14.8 g. of the R,S-a-benzoyloxy-butyric acid benzyl ester obtained abovewere dissolved in 300 ml. of alcohol and, with the addition of Pd/ C,hydrogenated up to the uptake of the theoretical amount of hydrogen. Thecatalyst was separated ed, the filtrate evaporated in a vacuum and theresidue dissolved in 300 ml. of ethyl acetate. The ethyl acetatesolution was washed with water and extracted twice with 100 ml. portionsof a 5 percent sodium bicarbonate solution. The alkaline solution wascooled with ice, made congo-acidic with 3 N hydrochloride acid andextracted with 300 ml. of ethyl acetate. The ethyl acetate solution waswashed with water, dried over magnesium sulphate and evaporated in avacuum. The R,S-a-benzoyloxybutyric acid thus obtained wasrecrystallized from ethyl acetate/ low-boiling petroleum ether. Meltingpoint -86.

(B) The process:

A solution of 10.4 g. of R,S-a-benzoyloxy-butyric acid in ml. ofabsolute chloroform which had been cooled to -15 was treated with 5.1 g.of triethylamine and 6.0 g. of pivaloyl chloride and stirred at -15 for30 minutes. A solution of 10.8 g. of 6-aminopenicillanic acid and 10.1g. of triethylamine in 100 ml. of absolute chloroform which had beencooled to '40 was then added. The solution was stirred at l0 for 3 hoursand left to stand at 4 for 48 hours. The solvent was evaporated off invacuo and the residue dissolved in 200 ml. of icewater. The aqueoussolution was extracted with two 100 ml. portions of ether, cooled to 2,adjusted to pH 2.5 with 1 N hydrochloric acid and extracted with two 250ml. portions of ethyl acetate. The ethyl acetate solution was washedwith two 250 ml. portions of water, dried over magnesium sulphate,concentrated to ca. 100 ml. in a vacuum and treated with 800 ml. of1ow-boiling petroleum ether. The precipitated[(R,S)-l-benzoyloxy-propyl]- penicillin was reprecipitated from ethylacetate and low- 11 boiling petroleum, ether, dried and dissolved in 100ml. of absolute ether. The solution was filtered and, with stirring andice-cooling, treated with 100 ml. of absolute ether which contained 25ml. of a 2 M solution of potassium 2-ethylcaproate in isopropanol. Afterthe addition of 700 ml. of low-boilingpetroleum ether, the precipitated[(R,S)-1-ben zoyloxy propyl] penicillin P tassium was filtered otf bysuction, washed with low-boiling petroleum ether, dried andrecrystallized from water/alcohol. Melting point 188"v (decomposition);+230 (c.=l.06 in water).

' EXAMPLE 9 (R 1-(4-chlorobenzoyloxy) -phenethyl1-penicillin potassium(A) The preparation of the starting material:

18.8 g. of R-2-hydroxy-3-phenylpropionic acid benzyl ester weredissolved in 150 ml. of of pyridine, the solution cooled to and treatedwith 13.0 g. of p-chlorobenzoyl chloride. After 1 hour, 20 ml. ofmethanol were added, the mixture allowed to stand for 15minutesanddiluted with ether. With ice-cooling, the mixture wassuccessively washed with dilute hydrochloric acid, water and dilutesodium bicarbonate solution. The solution was then dried over sodiumsulphate and concentrated.

The oily residue was hydrogenated in 200 ml. of alcohol withthe additionof 1 g. of palladium-charcoal catalyst. After the hydrogen uptake wascomplete, the mixture was filtered and concentrated. The residue wastaken up in ether and the acid extracted with dilute soda s lution.After acidification with dilute hydrochloric acid, the mixture wasshaken out with ether, the ethereal solution washed with water, driedover sodium sulphate and concentrated. The residue was crystallized fromcyclohexane. The resulting R-2-(4-chlorobenzoyloxy) -3-phenylpropionicacid melted at 139-l40; [w] +69.2 (c.=3.5 in alcohol).

(B) The process:

3.04 g. of R-2-(4-chlorobenzoyloxy)-3-phenylpropionic acid producedabove were heated at reflux for 2 hours in ml. of thionyl chloride. Themixture was subsequently concentrated to dryness and the residuesubjected twice to an azeotropic distillation with benzene. The residualoil (3.4 g.) was dissolved in 20 ml. of methylene chloride and added at0 with stirring to a solution of 2.16 g. of G-aminopenicillanic acid in30 ml. of methylene chloride and 2.8 ml. of triethylamine. After 2.5hours, the mix ture was concentrated in a vacuum at 30. The residue wasdissolved in water, the solution adjusted to pH 8 with potassiumbicarbonate and washed with ether. After acidification'to pH 2.2 with3 Nhydrochloric acid, the penicillin product was extracted with ethylacetate. After drying over'sodium sulphate, the solution was concen-'trated in vacuum at 3. f

The oily residue (5.2 g.) was dissolved in a little isopropanol-andtreated with 5 ml. of a 2 N solution of potassium Z-ethyl-cap'roate' inethyl acetate. [(R')-1-(4-chlorobenzoyloxy)-phenethyl] -penicillinpotassium was precipitated by the addition of isopropyl ether.Melting-point 145 (decomposition); [M +140.8 (c.=l.0 in alcohol).

EXAMPLE 10 (R,S)-1- (p-fiuorobenzoyloxy) -3-methyl'butyl] penicillinpotassium (A) The preparation of the starting material:

26.4 g. of R,S-u-hydroxyisocaproic acid was dissolved in 180.0 ml. ofabsolute dioxane in aVthree-necked vessel equipped with a stirrer,thermometer and reflux condenser. The resulting solution was treated insuccession with 28.5 ml. triethylamine and 23.5 ml. benzylchloride. Themixture was maintained for 20 hours with stirring at 100 in an oil bath.The mixture was then cooled and the triethylamine hydrochloride removedby suction filtration 12 and washed with 50.0 ml. of ethyl acetate. Thefiltrate was evaporated on a water pump vacuum at about 50 and theresulting oil taken. up in 80.0 ml. ethyl acetate and washedsuccessively with two 15 ml. portions of 3 N hydrochloric acid, two 10ml. portions of a 5% aqueous sodium chloride solution, two 15 ml.portions of a 10% aqueous potassium bicarbonate solution and two 10 ml.portions of a 5% aqueous sodium chloride solution. The wash liquids werecombined and extracted with 20.0 ml. of ethyl acetate. The ethyl acetatefractions were dried byshakin with magnesium sulfate and evaporated overa water pump vacuum at 50 to yield R,Sa-hydroxyisocaproic acid benzylester.

11.5 g. .of R,S-a-hydroxyisocaproic acid benzyl ester thus-formed weredissolved in 50 ml. of pyridine, the solution cooled to 0 and treatedwith 8.2 g. of 4-fiuoro-. benzoyl chloride. After 4.5 hours, 20 ml. ofmethanol wereadded and the mixture allowed to stand at room temperaturefor 50 minutes. The solution diluted with ether, Washed, withice-cooling, with dilute hydrochloric acid, water and sodium bicarbonatesolution, dried and concentrated.

The resulting oily residue was hydrogenated in 200 ml. of methanol withthe addition of 1 g. of 5% palladiumcharcoal catalyst. After thehydrogen uptake was complete, the mixture was filtered and concentrated.The residue was taken up in ether and the acid extracted with dilutesodium bicarbonate solution. After acidification with dilutehydrochloric acid, the mixture was extracted with ether, washed withwater and concentrated. R,S-a- (4-fluorobenzoyloxy)-isocaproic acid wasobtained as an oil.

(B) The process:

5.1 g. of R,S-a-(4-fluorobenzoyloxy) -isocaproic acid obtained abovewere heated at reflux for 1 hour in 20 ml. of thionyl chloride. Thesolution was concentrated and azeotroped twice with benzene. The oilyresidue (5.2 g.) was dissolved in 20' m1. of methylene chloride andadded at 0, with stirring, to a solution of 4.32. g. (20 mmol) ofG-aminopenicillanic acid in 20 ml. of methylene chloride and 5.6 ml. oftriethylamine. The solution was maintained at 0 overnight andsubsequently concentrated at 30. The residue was dissolved in water, thesolution adjusted to pH 8.0 with dilute sodium bicarbonate solution andwashed with etherl The solution was then acidified to pH 2.2. with 3 Nhydrochloric acid and the penicillin product extracted with ethylacetate. After washing with water, the solution was dried over sodiumsulphate and concentrated. The residue was dissolved in a littleisopropanol and treated with 10 ml. of a 2 N solution of potassium 2-ethylcaproate in ethyl acetate. By the addition of lowboiling petroleumether, there was precipitated [(R,S)-1- (p-fluorobenzoyloxy)-3-methylbutyl] penicillin potassium. Melting point (decomposition); [M+1736 (c.=1.0 in alcohol).

' EXAMPLE 11 [(R,S)-l (2-chloro-4-fluorobenzoyloxy)- propyl] penicillin(A) The preparation of the starting material:

A solution of 10.0 g. of 2-chloro-4-fiuorobenzoic acid, 148 g. ofR,S-ot-bromobutyric acid benzyl ester and 6.4 g. of triethylamine in 100ml. of absolute dioxan was boiled under reflux for 20 hours. Aftercooling, the triethylamine hydrobromide was filtered otf 'by suction andthe filtrate evaporated in a vacuum. The residue was dissolved in 300ml. of ethyl acetate. The ethyl acetate solution was Washed with waterand ice-cold 5 percent sodium bicarbonate solution, dried over magnesiumsulphate and evaporated in a vacuum. The residual R,S-a-(2-chloro-4-fluorobenzoyloxy)-butyric acid benzyl ester was distilled in a highvacuum. Boiling point 132/0.05 mm. Hg.

9.4 g. of the resulting R,S-a-(2-chloro-4-fiuorobenzoy1- oxy)-butyricacid benzyl ester were dissolved in 200 ml. of alcohol and, with theaddition of Pd/C catalyst,

hydrogenated up to the uptake of the theoretical amount of hydrogen. Thecatalyst was separated off, the filtrate evaporated in a vacuum and theresidue dissolved in 200 ml. of ethyl acetate. The ethyl acetatesolution was washed with water and extracted twice with 80 ml. portionsof percent sodium bicarbonate solution. The alkaline solution was cooledwith ice, made congo-acidic with concentrated hydrochloric acid andextracted with 200 ml. of ethyl acetate. The ethyl acetate solution waswashed with water, dried over magnesium sulphate and evaporated in avacuum. The R,S-a-(2-chloro 4 fiuorobenzoyloxy)-butyric acid thusobtained was recrystallized from cyclohexane. Melting point 83 84..

(B) The process:

A solution of 3.7 g. of R,S-oc-(2-chloro-4-fluorobenzoyloxy)-butyricacid in 50 ml. of absolute chloroform was cooled to and treated with 1.4g. of triethylamine and 1.7 g. of pivaloyl chloride and stirred at --15for 30 minutes. A solution of 3.0 g. of 6-aminopenicillanic acid and 2.8g. of triethylamine in 50 ml. of absolute chloroform which had beencooled to 40 was then added. The mixture was stirred at --10 for 3 hoursand left to stand at 4 for 48 hours. The solvent was then evaporated offin a vacuum and the residue dissolved in 100 ml. of ice-water. Theaqueous solution was extracted twice with 50 ml. of ether, cooled to 2,adjusted to pH 2.1 with 1 "N hydrochloric acid and extracted twice with-100 ml. portions of ethyl acetate. The ethyl acetate solution was washedtwice with 100 ml. portions of water, dried over magnesium sulphate,concentrated to ca. 50 ml. in a vacuum and treated with 400 ml. oflow-boiling petroleum ether. The precipitated [('R,S)-1-(2-chloro-4-fluorobenzoyloxy)-propyl] -penicillin was reprecipitated from ethylacetate and low-boiling petroleum ether, dried and dissolved in 100 ml.of absolute ether. The solution was filtared and, with ice-cooling,treated with 100 ml. of absolute ether which contained 7 ml. of a 2 Msolution of potassium 2.-ethylcaproate in isopropanol. After theaddition of 200 ml. of absolute ether, the precipitated[('R,S)-l1-(2-chloro 4 fiuorobenzoyloxy) -propyl] -penicillin potasiumwas filtered off by suction, washed with absolute ether and dried.Melting point 150 (decomposition); +139 (c.=1 in water).

EXAMPLE 12 (R,S -1-( 3-bromobenzoyloxy) -pentyl] -penicillin (A) Thepreparation of the starting material:

LA solution of 30.2 g. of m-bromobenzoic acid, 25.1 g. of-R,S-a-bromocaproic acid t-butyl ester and 16.2 g. of triethylamine in250 ml. of absolute dimethylformamide was stirred at 100 for hours andthen evaporated to' dryness in a vacuum. With stirring, the residue wasdissolved in a mixture of 600 ml. of ethyl acetate and 300 ml. of water.The ethyl acetate phase was then washed into 300 ml. of water, twicewith 200 ml. portions of ice-cold 5 percent sodium bicarbonate solutionand twice with 200 ml. portions of water, dried over magnesium sulphateand evaporated to dryness in a vacuum. The residualR,S-a-(3-bromobenzoyloxy)-caproic acid t-butyl ester was dissolved in 50ml. of anhydrous trifluoroacetic acid. After standing at roomtemperature for 30 minutes, the solution was evaporated to dryness in avacuum. The R,S-e-(3-bromobenzoyloxy)-caproic acid thus obtained wasrecrystallized from cyclohexane/low-boiling petroleum ether. Meltingpoint 79-80.

(B) The process:

A solution of 12.6 g. of R,S-a-(3-bromobenzoyloxy)- caproic acid in 100ml. of absolute chloroform was cooled to -15 and treated with 4.0 g. oftriethylamine in 4.8 g. of pivaloyl chloride and stirred at -15 for 30minutes. A solution of 8.7 g. of 6-aminopenicillanic acid and 8.1 g. oftriethylamine in 100 ml. of absolute chloroform, cooled to -40", wasthen added. The solution was then stirred at 10 for 3 hours andmaintianed at 4 for 48 hours. The solvent was then evaporated off in avacuum and'the residue dissolved in 200 ml. of ice-water. The aqueousSolution was extracted twice with ml. portions of ether, cooled to 2,adjusted to pH 2.5 with 1 N hydrochloric acid and extracted twice with250 ml. portions of ethyl acetate. The ethyl acetate solution was washedtwice with 250 ml. portions of water, dried over magnesium sulphate,concentrated to ca. 100 ml. in a vacuum and treated with 800 ml. oflow-boiling petroleum ether. The precipitated (R,S) -l-3-bromobenzoyloxy) -pentyl] -penicillin was reprecipitated from ethylacetate and low-boiling petroleum ether, dried and dissolved in 200 ml.of absolute ether. The solution was filtered and, with stirring andice-cooling, treated with 200 ml. of absolute ether which contained 20ml. of a 2 M solution of potassium Z-ethylcaproate in ethyl acetate.After the addition of 600 ml. of low-boiling petroleum ether, theprecipitated [(R,S)-1-(3-bromobenzoyloxy)-pentyl] penicillin potassiumwas filtered off by suction, washed with low-boiling petroleum ether anddried. Melting point (decomposition); [0:1 +137 (c. =1 in water).

EXAMPLE 13 [(R,S)-l-(2-chlorobenzoyloxy) -pentyl]- penicillin potassium(A) The preparation of the starting material:

A solution of 42.2 g. of R,S-u-hydroxycaproic acid benzyl ester in 150ml. of absolute pyridine was cooled to -15 and treated over a period of15 minutes with a solution of 38.5 g. of 3-chlorobenzoyl chloride in 50ml. of absolute tetrahydrofuran. The mixture was stirred at roomtemperature for 70 hours and subsequently evaporated to dryness in avacuum. The residue was dissolved and stirred in a mixture of 300 ml. ofethyl acetate and 150 ml. of water. The ethyl acetate phase was washedtwice with 150 ml. portions of ice-cold 5 percent sodium bicarbonatesolution, twice with 150 ml. portions of 1 N hydrochloric acid and with150 ml. of water, dried over magnesium sulphate and evaporated todryness in a vacuum. The residue, R,S-a-(2-chlorobenzoyloxy)-caproicacid benzyl ester, was dissolved in 1000 ml. of alcohol and, with theaddition of Pd/ C, hydrogenated up to the uptake of the theoreticalamount of hydrogen. The catalyst was separated otf, the filtrateevaporated in a vacuum and the residue dissolved in 450 ml. of ethylacetate. The ethyl acetate solution was washed with water and extractedtwice with 250 ml. portions of ice-cold 5 percent sodium bicarbonatesolution. The alkaline solution was cooled with ice, made congo-acidicwith concentrated hydrochloric acid and extnacted with 500 m1. of ethylacetate. The ethyl acetate solution was-washed with water, dried overmagnesium sulphate and evaporated in a vacuum. The R,S-a-(2-chlorobenzoyloxy)-caproic acid thus obtained was recrystallized fromcyclohexane/low-boiling petroleum ether. Melting point 65 -66.

(B) The process:

A solution of 13.5 g. of R,S-u-(2-chlorobenzoyloxy)- caproic acid in 100ml. of absolute chloroform was cooled to -15 and treated with 5.1 g. oftriethylamine in 6.0 g. of pivaloyl chloride and stirred at 15 for 30minutes. A solution of 10.8 g. of 6-aminopenicillanic acid and 10.1 g.of triethylamine in 100 ml. of absolute chloroform was cooled to -40 andthen added. The solution was stirred at 10 for 3 hours and maintained at4 for 48 hours. The solvent was evaporated oif in a vacuum and theresidue dissolved in 150 ml. of ice-water. The aqueous solution wasextracted twice with 100 ml. portions of ether, cooled to 2, adjusted topH 2.2 with 1 N hydrochloric acid and extracted twice with 250 ml. ofethyl acetate. The ethyl acetate solution was washed twice with 250 ml.portions of water, dried over magnesium sulphate, concentrated to ca.100 ml. in a vacuum and treated with 800 ml. of low-boiling petroleumether. The precipitated [(R,S)-1-(2-chlorobenzoyloxy)-pentyl]-penicillinwas retion); [ah- +161 (c.=1 in water).

dried. Melting point 147 (decomposition); abal-. 46",

(c.=1 in water).

' EXAMPLE 1 4 R,S -1- (4-chlorobenzoyloxy) pentyl] -p 'e "r'ii cillin(A) The preparation of the starting material: I

A solution of 39.0 g. of R, S-a-hydroxycaproic acid benzyl ester in 100ml. of absolute pyridine was cooled to and treated over a period ofminutes with'a" solution of 35.0 g. of 4-chlorobenz'oyl chloride in 50'm1. --i of absolute tetrahydrofuran. The mixture was stirred at roomtemperature for 20 hours and subsequently evaporated to dryness in avacuum. With stirring, the residue was dissolved in a mixture of 300 ml.of ethyl acetate and 150 ml. of water. The ethyl acetate phase waswashed twice with 150 ml. portions of ice-cold 5 percent sodiumbicarbonate solution, twice with 150 m1. portions of 1 N hydrochloricacid and with 150 ml. of water, dried over magnesium sulphate andevaporated to dryness in-a vacuum. The residual R,Sx-(4-chlorobenzoyloxy)-caproic acid benzyl ester was dissolved in 800ml. of alcohol and, with the addition of Pd/ C, hydrogenated up to theuptake of the theoretical amount of hydrogen. The catalyst was separatedoff, the filtrate evaporated in a vacuum and the residue dissolved in400 ml. of ethyl acetate. The ethyl acetate solution was washed withwater and extracted twice with 200 ml. portions of ice-cold'S percentsodium bicarbonate solution. The alkaline solution was cooled with ice,made congo-acidic with concentrated hy-' (A) The preparation of thestarting material: A solution of 23.5 g. of 4-chlorobenzoic acid, 23.7g.

of R,S-ot-bromovaleric acid t-butyl ester and 15.2 g. of triethylaminein 200 ml. of absolute dimethylformamrde wasstirred at room temperaturefor 18 hours and at 100 for "2 hours and subsequently evaporated todryness ina vacuum. With stirring, the residue was dissolved in amixture of 500 ml. of ethyl acetate and 200 ml. of water. The

ethyl acetate phase was washed twice with 150 ml. por- 7 tions otice-cold 5 percent sodium bicarbonate solution drochloric acid andextracted with 500 ml. of ethyl acetate.

A solution of 10.8 g. of G-aminopenicillanic acid and. 10.1

g. of triethylamine in 100 ml. of absolute chloroform was" cooled to -40and then added. The solution was stirred at -10 for 3 hours andmaintained at 4 for td-hours. The solvent was removed in a vacuum andthe residue dissolved in 150 ml. of ice-water. The solution was extracted with twice 100 ml. portions of ether cooled to 2, adjusted to pH2.0 with 1 N hydrochloric acid and extracted twice with 250 ml. portionsof ethyl acetate.

The ethyl acetate solution was washed with twice 250 ml. portions ofwater, dried over magnesium sulphate,

concentrated to ca. 100 mLin a vacuum and treated with 800 ml. oflow-boiling petroleum ether. The precipitated [(R,S) 1 (4chlorobenzoyloxy) pentyl] penicillin was reprecipitated from ethylacetate and low-boiling petroleum ether, dried and dissolved in 100 ml.of absolute ether. The solution was filtered and, with stirring andice-cooling, treated with 100 ml. of absolute ether which contained 20ml. of a 2 M solution of potassium 2-ethylcaproate in ethyl acetate.After the addition of 700ml. of low-boiling petroleum ether, theprecipitated [(R,S)-1- (4 chlorobenzoyloxy) pentyl] penicillin potassiumwas filtered off by suction, washed with low-boiling petroleum ether anddried. Melting point 165 (decomposi and twice with 150 ml. portions ofwater, dried over magnesium sulphate and evaporated to dryness in avacuurn. The residual R,S a (4 chlorobenzoyloxy) valeric acidt-butylester was'disso lved in 50ml. of anhydrous trifiuoro'acetic acid. Afterstanding at room temperature for '1 30'n'1inutes, the solution wasevaporated' to dryness in a: vacuum. The R,S, -E i-(4 chloro'b en'zoyloxy) valeric 'acicl thus obtained was recrystallized fromcyclohexane/low-" boiling petroleum ether. Melting point 6264.

(B) The process:

Asolution at 10.2 of R,S oz 4 chlorobenzoyloxy)- valeric acid in ml. ofabsolute chloroform was cooled to 15 and treated with 4.0 g. oftriethylamine and 4.8 g. of pivaloyl chloride and stirred at --15 for 30minutes. A solution of 8.7 g. of 6-aminopenicillan'ic acid and 8.1 g.

' of triethylamine in 100 ml. of absolute chloroform was cooled to 40and then added. The solution was stirred I I at --10 for 3 hours andmaintained at 4 for 48 hours. The solvent was evaporated off in a vacuumand the residue dissolved in ml. of ice-water. The solution wasextracted twice with 100 ml. portions of ether cooled to 2, adjusted topH 2.0 with 3 N hydrochloric acid and extracted twice with 250 ml.portions of ethyl acetate. The ethyl acetate solution was washed twicewith 250 ml. portions of water, dried over magnesium sulphate,concentrated to ca. 100 mlQ in a vacuum and treated with 800 ml. oflow-boiling petroleum ether. The precipitated [R,S) l (4chlorobenzoyloxy) butyl] penicillin was reprecipitated from ethylacetate and low-boiling petroleum ether, dried and dissolved in 100 ml.of absolute ether. The solution was filtered and, with stirring andice-cooling, treated with 50 ml. of absolute ether which contained 18ml. of 2 M solution of potassium 2- ethylcaproatein ethyl acetate. Afterthe addition of 800 7 ml. of low-boiling petroleum ether, theprecipitated [(R,

S) 1 (4 chlorobenzoyloxy) butyl] penicillin potassium was filtered on bysuction, washed with low-boiling 'petroleum ether and dried. Meltingpoint 150 (decomposition); [a] '(c.='l in water).

EXAMPLE 16 [R,S) l (4-chlorobenzoyloxy) -hexyl] -penicillin perature for20 hours and subsequently evaporated to dryness in a vacuum. The residuewas dissolved in a mixture of 500 ml. of ethyl acetate and 250 ml. ofwater. The ethyl acetate was washed twice with 150 ml. portions ofice-cold 5 percent sodium bicarbonate solution, twice with 150 ml.portions of 1 N hydrochloric acid and twice with 150 ml. portions ofwater, dried over magnesium sulphate and evaporated to dryness in avacuum. The residue R,S-a-(4-chlorobenzoyloxy)-enanthic acid benzylester wasdissolved in 1000 ml. of alcohol and, with the addition ofPd/C, hydrogenated up to the uptake of the theoretical amount ofhydrogen. The catalyst was sep- 17 arated off, the filtrate evaporatedin a vacuum and the residue dissolved in 350 ml. of ethyl acetate. Thesolution was washed with water and extracted twice with 250 ml. portionsof ice-cold percent sodium bicarbonate solution each time. The alkalinesolution was then cooled with ice, made Congo-acidic with concentratedhydrochloric acid and extracted with 500 ml. of ethyl acetate. The ethylacetate solution was washed with water, dried over magnesium sulphateand evaporated in a vacuum. The R,S-a-(4-chlorobenzoyloxy)-ena11thicacid thus obtained was recrystallized from low-boiling petroleum ether.Melt ing point 7475.

(B) The process:

A solution of 12.8 g. of the R,S-oc-(4 chlorobenzoyloxy)-enanthic acidthus obtained in 100 ml. of absolute chloroform was cooled to l5 andtreated with 4.6 g. of triethylamine and 5.4 g. of pivaloyl chloride andstirred at 15 for 30 minutes. A solution of 9.8 g. of6-aminopenicillanic acid and 9.1 g. of triethylamine in 100 ml. ofabsolute chloroform was cooled to --40 and then added. The solution wasstirred at -10 for 3 hours and maintained at 4 for 48 hours. The solventwas evaporated off in a vacuum and the residue dissolved in 150 ml. ofice-water. The solution was extracted twice with 100 ml. portions ofether, cooled to 2, adjusted to pH 2.0 with 3 N hydrochloric acid andextracted twice with 250 ml. portions of ethyl acetate. The ethylacetate solution was washed twice with 250 ml. of water each time, driedover magnesium sulphate, concentrated to ca. 100 ml. in a vacuum andtreated with 800 ml. of low-boiling petroleum ether. The precipitated[(R,S)-1-(4 chlorobenzoyloxy)-hexyl]-penicillin was reprecipitated fromethyl acetate and low-boiling petroleum ether, dried and dissolved in100 ml. of ether. The solution was treated with stirring, with anice-cold solution of 3.4 g. of sodium bicarbonate in 50 ml. of water.The ether was evaporated OR in a vacuum and the aqueous solutionadjusted to pH 6.0 with glacial acetic acid, diluted with 300 m1. ofisopropanol and evaporated to dryness in a vacuum. The residue wasdissolved in 200 ml. of ethyl acetate. The solution was filtered andtreated with 800 ml. of lowboiling petroleum ether. The precipitated[(R,S)-1-(4- chlorobenzoyloxy)-hexyl]-penicillin sodium was filtered offby suction, washed with low-boiling petroleum ether, dissolved in 200ml. of ethyl acetate, again precipitated by addition of 800 ml. oflow-boiling petroleum ether, filtered off by suction and dried. Meltingpoint 177 (decomposition); +158 (c.=1 in water).

EXAMPLE 17 (R,S) -.1-(4-chlorobenzoyloxy) -3-butenyl] -penicillinpotassium (A) The preparation of the starting material:

49.6 g. of 2-allylglycine in 35.0 g. of freshly melted sodium acetatewere treated in 600 ml. of glacial acetic acid at 2030 with 59.0 g. ofisoamyl nitrate over a period of 3 hours. The mixture was stirred at20-30 for 24 hours and then evaporated under reduced pressure. Theresidue was partitioned between water and ether and the etherealsolution washed with 10% potassium hydrogen carbonate solution. Theaqueous phases were made congoacidic and extracted with ether. Theethereal solution was washed with water, dried and evaporated. There wasobtained 45.1 g. of oily R,S-2-acetoxy-4-pentenoic acid which wasdissolved at -l0 in 600 ml. of methylene chloride, 600 ml. of isobuteneand 4 ml. of concentrated sulphuric acid. After standing at roomtemperature for 44 hours, the isobutene was evaporated OE and themethylene chloride solution washed with 10% potassium hydrogen carbonatesolution, dried and evaporated. There was obtained oily R,S-2-acetoxy-4pentenoic acid tertbutyl ester of boiling point 47/ 0.1 mm.; n =l.4268.

46.4 g. of the foregoing ester were treated in 50 ml. of methanol and 25ml. of water at 10 with stirring over a period of 15 minutes with 108ml. of 2 N caustic soda. The mixture Was stirred at room temperature for4 hours and then extracted with ether. Working up of the etherealextract yielded 34.9 g. of crude R,S-2-.hydroxy-4-pentenoic acidtertbutyl ester. The ester was treated in 200 ml. of pyridine at 5 overa period of 15 minutes with 35.0 g. of p-chlorobenzoyl chloride. Themixture was allowed to warm to room temperature, the pyridine evaporatedolf and the residue partitioned between ether and 10% potassium hydrogencarbonate solution. The ethereal phase was worked up and yielded 62.7 g.of crude 2-(4-chlorobenzoyloxy)-4-pentenoic acid tertbutyl ester whichwas allowed to stand at room temperature for 30 minutes with ml. oftrilluoroacetic acid. The acid was then removed under reduced pressure,the residue taken up in ether and the ethereal solution exhaustivelyextracted with 10% potassium hydrogen carbonate solution. The aqueousphase was made congo-acidic and extracted with ether. Working up of theethereal phase yielded 2-(4-chlorobenzoyloxy)-4-pentenoic acid ofmelting point 56-58 (from hexane).

(B) The process:

A solution of 10.2 g. of R,S-2-(4-chlorobenzoyloxy)-4- pentenoic acid,formed above, in 120 ml. of absolute chloroform was cooled to -15 andtreated with 5.6 ml. of triethylamine and 4.8 g. of pivaloyl chlorideand stirred at -l5 for 20 minutes. A solution of 8.7 g. of6-aminopenicillanic acid and 11.2 ml. of triethylamine in 200 ml. ofchloroform was cooled to 40 and then added. The solution was stirred at-10 for 3 hours and then maintained at 4 for 70 hours. The solvent wasevaporated oil in a vacuum and the residue dissolved in 20 0 ml. ofice-water. The solution was extracted twice with ml. portions of ether,cooled to 2", adjusted to about pH 2 with 1 N hydrochloric acid andextracted twice with 250 ml. portions of ethyl acetate. The ethylacetate solution was washed with water, dried and concentrated to avolume of 80 ml. On the addition of 800 ml. of lowboiling petroleumether, there precipitated [(R,S)-1-(4-chlorobenzoyloxy)-3-butenyl]-penicillin. The product was reprecipitatedfrom ethyl acetate and low-boiling petroleum ether, dried and thendissolved in 200 ml. of absolute ether. With stirring and ice-cooling,the solution was treated with 100 m1. of absolute ether which contained20 ml. of a 2 M solution of potassium 2-ethylcaproate in ethyl acetate.700 ml. of low-boiling petroleum ether were then added and theprecipitate filtered oif. There was obtained 5.8 g. of[(R,S)-1-(4-chlorobenzoyloxyl)-3-butenyl]-penicillin potassium ofmelting point 185 (decomposition); [a] =+205.6 (c.= 1 in water).

EXAMPLE 18 (R,S)-1-(4-hydroxymethyl-benzoyloxy)-3-methylbutyl]-penicillin sodium (A) The preparation of the starting material:

9.4 g. of (R,S,)-a-bromo-isocaproic acid benzyl ester and 8.5 g. of thesodium salt of p-hydroxymethylbenzoic acid tetrahydropyranyl ether wereheated to in 100 ml. of dimethylformamide for 4.5 hours with stirring.The mixture was subsequently cooled, diluted with water and extractedwith ether. The ethereal solution was washed with dilute sodiumbicarbonate solution and water, dried over sodium sulphate andconcentrated in a vacuum. The (R,S)a-(4-tetrahydropyranyloxymethylbenzoyloxy)-isocaproic acid benzyl esterthus formed was hydrogenated in methanol with the addition of Pd./C. Thecatalyst was then separated oil and the filtrate evaporated in a vacuum.(R,S,) 0c (4-tetrahydropyranyloxymethylbenzoyloxy)- isocaproic acid wasobtained as a yellow-brown oil (8.5 g.).

(B) The process:

8.5 g. of (R,S)-a-(4-tetrahydropyranyloxymethylbenzoyloxy)-isocaproicacid formed above were dissolved in 300 ml. of absolute tetrahydrofuran.3,4 ml. of triethylamine were added, the mixture cooled to and 3.72 ml.of chloroformic acid isobutyl ester added dropwise with stirring. Themixture was stirred at 0 for 3 hours and then a solution of 5.25 g. of6-aminopenicillanic acid in 30 m1. of methylene chloride and 10.2 ml. oftriethylamine was added. After stirring for 2 hours, the mixture wasfiltere and concentrated in a vacuum.

The residue was dissolved in water and the solution washed with ether.It was then acidified to pH 2 with dilute hydrochloric acid and theprecipitated penicillin product extracted with ethyl acetate. The ethylacetate solution was washed with water, dried over sodium sulphate andconcentrated in a vacuum. The residue was dissolved in isopropanol andtreated with ml. of a 2 N solution of sodium ethylcaproate in. ethylacetate. By addition of isopropyl ether, there was precipitated[(R,S)-1-(4- hydroxymethylbenzoyloxy) 3 methylbutylJ-penicillin sodiumin a yield of 10.0 g. Melting point 200 (decomposition); [a] l04.6 (c.=1in alcohol).

EXAMPLE 19 (R l 4-methoxymethyl-benzoyloxy) -3 -methylbutyl] penicillinsodium (A) The preparation of the starting material:

26.4 g. of (R,S)-u-hydroxy-isocaproic acid were dissolved in 650.0 ml.of cold, absolute acetonitrile. The resulting solution was treated with24.2 g. of (+)-phenylethylamine and allowed to crystallize over a periodof 3 hours at 20 with stirring. The crystalline mass was filtered,washed with 100.0 ml. of cold absolute acetonitrile and filtered under avacuum at 60 to yield the (+)-phenylethylamine salt of Ru-hydroxyisocaproic acid. [0:3 =+25.5 (c.==2 in methanol).

19.8 g. of the (+)-phenylethylamine salt of R-vc-hY- droxyisocaproicacid thus formed was dissolved in 65 ml. of 3 N hydrochloric acid andextracted three times with 100 m1. portions of ether (the hydrochloricacid phase must be acidic to Congo reagent). The ether extract waswashed three times with 25 ml. portions of a 5% aqueous sodium chloridesolution, dried over sodium sulfate and 20 to 10 in 100 ml. of absolutetetrahydrofurau. 13.3 g. of p-methoxymethylbenzoylchloride in 75 ml. of.absolute tetrahydrofuran were added dropwise with stirring. Aftercompletion of the addition, the mixture was stirredovernight at roomtemperature. It was subsequently concentrated to dryness in a vacuum.The residue was taken up in ethyl acetate and the solution obtainedsuccessively washed with dilute hydrochloric acid, water, dilute sodiumbicarbonate solution and water. After drying over sodium sulphate, thesolution was concentrated ina vacuum. The

residue was hydrogenated in methanol with the addition 1' 1 of Pd/C.After removal of the catalyst, the solution was concentrated in avacuum. The residue was dissolved in ethyl acetate and the acidextracted with l-N caustic soda.

The solution obtained was acidified with dilute hydrochloric acid andthe acid extracted with ethyl acetate. After washing with water anddrying over sodium sulphate, the ethyl acetate extract was concentratedin a vacuum. (R)1-(4-Methoxymethylbenzoyloxy)sisocaproic acid wasobtained as an oily residue (12.8 g").

(B) The process:

12.8 g. of (R)u-(4 methoxymethylbenzoyloxy) -iso caproic acid obtainedabove were heated at reflux for 2 hours in 50 ml. of absolute benzeneand 50 ml. of thionyl chloride. The mixture was then concentrated todryness in a vacuum and azeotroped twice with benzene. The oily residuewas dissolved in 50 ml. of methylene chloride and introduced at 0 withstirring into a solution of 9.8 g. of 6-aminopenicillanic acid in 50 ml.of methylene chloride and 19.2, ml. of triethylamine. The mixture wasmaintained overnight at 0 and then concentrated to dryness in a vacuum.The residue was taken up in water and the soltuion washed with ether. Itwas subsequently acidified to pH 2.5 with dilute hydrochloric acid andthe precipitated penicillin product extracted with ethyl acetate. Theethyl acetate solution was washed with water, dried over sodium sulphateand concentrated in a vacuum. The residue was dissolved in isopropanoland treated with 19.1

ml. of a 2 N solution of sodium ethylcaproate in ethyl acetate. By theaddition of isopropyl ether, there was preevaporated under vacuum. Theoily product was mixed 180.0 ml. of absolute dioxane in a three-neckedvessel equipped with a stirrer, thermometer and reflux condenser. Theresulting solution was treated in succession with 28.5 ml. triethylamineand 23.5 ml. benzylchloride. The mixture was maintained for 20 hourswith stirring at 100 in an oil bath. The mixture was then cooled and thetriethylamine hydrochloride removed by suction filtration and washedwith 50.0 ml. of ethyl acetate. The filtrate was evaporated on a waterpump vacuum at about 50 and the resulting oil taken up in 80.0 ml. ethylacetate and washed successively with two 15 ml. portions of 3 Nhydrochloric acid, two 10 ml. portions of a 5% aqueous sodium chloridesolution, two 15 m1. portions of a 10% aqueous potassium bicarbonatesolution and two 10 ml. portions of a 5% aqueous sodium chloridesolution. The wash liquids were combined and extracted with 20.0 ml. ofethyl acetate. The ethyl acetate fractions were dried by shaking withmagnesium sulfate and evaporated over a water pump vacuum at 50 to yieldR-u-hydroxyisocaproic acid benzyl ester, R: [a]- =-+18.0 (0.: 1.0 inmethanol).

16.0 g. of the thus-formed (R)-a-hydroxyisocaproic acid benzyl ester and10.5 all Of triethylamine were milled cipitated [(R) 1 (4methoxymethylbenzoyloxy) 3- methylbutyH-penicillin sodium in-a yield of11.9 g. Melting point (decomposition); +l69.4'(c.= 1 in l alcohol). a

EXAMPLE 20 (R) -1- (4-acetoxymethyl-benzoyloxy)3-methylbutyI]-penici1lin sodium (A) The preparation of the starting material:

6.86 g. of (R)-a-hydroxyisocaproic acid benzyl ester and 4.5 ml. oftriethylamine were cooled to 10 in 50 ml. of absolutetetrahydrofuran.-6.87 g. of p-ace'toxymeth ylbenzoyl chloride in 50 ml.of absolute tetrahydrofuran were added dropwise with stirring; Themixture was allowed to stand overnight at room temperature and thenconcentrated in a vacuum. The residue was tak'en up in ethyl acetate andthe solution successively washed with 21 EXAMPLE 21 a (R) -3-methyl- 1-4-phenyl-benzoyloxy) -butyl] penicillin sodium (A) The preparation ofthe starting material:

6.65 g. of (R)-a-hydroxyisocaproic acid benzyl ester and 8.4 ml. oftriethylamine were dissolved in 100 ml. of absolute tetrahydrofuran andthe solution cooled to 15. 6.5 g. of 4-phenylbenzoyl chloride in 50 ml.of absolute tetrahydrofuran were added dropwise with stirring over aperiod of 15 minutes. After completion of the addition, the mixture wasstirred overnight at room temperature. The solution was subsequentlyconcentrated in a vacuum. The residue was then taken up in ether and theacid extracted with sodium bicarbonate solution. The sodium bicarbonatesolution was acidified with dilute hydrochloric acid, the acid taken upin ether and the ethereal solution washed with water. After drying oversodium sulphate, the solution was concentrated in a vacuum. (R)-a-(4-phenylbenzoyloxy)-isocaproic acid was obtained as an oily residue(4.3 g.).

(B) The process:

Starting from the (R) a (4-phenylbenzoyloxy)-isocaproic acid obtainedabove according to the procedure described in Example 19 there wasobtained [(R)-3-methyl-1-(4 phenylbenzoyloxy)-butyl]-penicillin sodiumof melting point 225 (decomposition); [u] +126.4 (0. =1 in water).

EXAMPLE 22 [(R,S)-1-(4-trifluoromethyl-benzoyloxy)-butyl]- pencillinsodium (A) The preparation of the starting material:

A solution of 28.4 g. of (R,S)-u-bromo-valeric acid tbutyl ester, 25.0g. of 4-trifluoromethyl-benzoic acid and 13.4 g. of triethylamine in 200ml. of absolute dimethylformamide was stirred at 25 for 15 hours and at100 for 2 hours and subsequently evaporated in a vacuum. The residue wasdissolved in a mixture of 400 ml. of ethyl acetate and 150 ml. of water.The ethyl acetate phase was washed with ice-cold 5% sodium bicarbonatesolution and water, dried over magnesium sulphate and evaporated in avacuum. The (R,S)-a-(4-trifluoromethylbenzoyloxy)- valeric acid t-butylester thus obtained was dissolved in 50 ml. of anhydrous trifluoroaceticacid. The solution was allowed to stand at 25 for 30 minutes and thenevaporated in a vacuum. The residue was dissolved in 50 ml. of absolutebenzene and the solution again evaporated in a vacuum. The(R,S)-a-(4-trifiuoromethyl-benzoyloxy)- valeric acid thus obtained wasrecrystallized from cyclohexane. Melting point 71-72.

(B) The process:

A solution of 13.1 g. of (R,S)-a-(4-trifluoromethylbenzoyloxy)-valericacid obtained above in 100 m1. of absolute chloroform was cooled to- 15and treated with 4.6 g. of triethylamine and 5.4 g. of pivaloyl chlorideand stirred at 15 for 30 minutes. A solution of 9.8 g. of6-aminopenicillanic acid and 9.1 g. of triethylamine in 100 ml. ofabsolute chloroform was cooled to 40 and then added. The solution wasstirred at 10 for about 3 hours and maintained at 4 for 48 hours. Thesolvent was removed in a vacuum and the residue dissolved in 150 ml. ofice-water. The solution was extracted with two 100 ml. portions ofether, cooled to 2, adjusted to pH 2.0 with 3 N hydrochloric acid andextracted with two 250 ml. portions of ethyl acetate. The ethyl acetatesolution was washed with two 250 m1. portions of water, dried overmagnesium sulphate, concentrated to ca 100 ml. in a vacuum and treatedwith 800 ml. of low-boiling petroleum ether. The precipitated[(R,S)-l-(4-trifiuoromethylbenzoyloxy)-butyl]-penicillin wasreprecipitated from ethyl acetate and low-boiling petroleum ether, driedand dissolved in 50 ml. of ethyl acetate. The solution was treated withan ice-cold solution of 3.3 g. of sodium bicarbonate in 50 ml. of waterand vigorously and thoroughly shaken. The ethyl acetate was removed in avacuum.

The aqueous solution was adjusted to pH 6.0 with glacial acetic acid,diluted with 200 m1. of isopropanol and evaporated to dryness in avacuum. The residue was dissolved in 150 ml. of ethyl acetate, thesolution filtered and evaporated in a vacuum. The residue was dissolvedin 150 ml. of ethyl acetate, the solution filtered and treated with 800ml. of low-boiling petroleum ether. The precipitated [(R,S) 1(4-trifluoromethylbenzoyloxy)butyl]-penicillin sodium was filtered offby suction, Washed with lowboiling petroleum ether, reprecipitated fromethyl acetate and low-boiling petroleum ether and dried. Melting point89 1 (c.=3.00 in dimethylformamide).

EXAMPLE 23 (R) 1- (4-aminomethyl-benzoyloxy) -3-methylbutyl] -penicillin(A) The preparation of the starting material:

23.0 g. of p-cyano-benzoic acid were heated under reflux for 2.5 hoursin 70 ml. of benzene, 40 m1. of thionyl chloride and 3 drops ofdimethylformamide. The solution was evaporated in a vacuum and theresidue dried. The resulting crude p-cyano-benzoyl chloride wasdissolved in 50 ml. of tetrahydrofuran, added dropwise with stirring at5 to a solution of 34.0 g. of Dm-hydroxyisocaproic acid benzyl ester in250 ml. of tetrahydrofuran and 22.5 ml. of triethylamine and stirred at0 for 1 hour and at 25 for 20 hours. The triethylamine hydrochloride wasfiltered off, the filtrate evaporated in a vacuum at 40, the residuedissolved in 250 ml. of ethyl acetate, washed with l-N hydrochloricacid, water, 8% sodium bicarbonate solution and water, dried overmagnesium sulphate and evaporated in a vacuum at 40. The resulting oilwas crystallized from alcohol to yield(R)-a-(p-cyanobenzoyloxy)-isocaproic acid benzyl ester of melting point88- 89 -1 (c.=3.00 in dimethylformamide).

25.6 g. of (R)-u-(p-cyanobenzoyloxy)-isocaproic acid benzyl ester werehydrogenated in 250 ml. of dimethylformamide and 25 ml. of 3 Nhydrochloric acid with 5% palladium-charcoal. The catalyst Was filteredoil, the filtrate adjusted to pH 7 with triethylamine, evaporated to avolume of 30 ml. in a vacuum, mixed with 300 ml. of alcohol, filteredoff and dried. There was thus obtained (R) -on(p-aminomethylbenzoyloxy)-isocaproic acid of melting point 246-247; [0:]+7.0 (c=2.00 in 1 N hydrochloric acid).

19.0 g. of (R) a (p-aminomethylbenzoyloxy)-iso caproic acid weredissolved in 200 ml. of water, 400 ml. of dioxan and 10.0 g. ofpotassium carbonate and, over a period of 10 minutes treated portionwisewith a solution of 14.0 g. of o-nitrophenylsulphenyl chloride in 300 ml.of dioxan. The pH was held between 7-8 by the addition of a littlepotassium carbonate. After 20 minutes, the solution was filtered,evaporated to a volume of ml. in a vacuum at 30, diluted with 100 m1. ofwater and extracted with 100 ml. of ether. The aqueous phase wasadjusted to pH 2 at 0 with 3 N sulphuric acid, extracted twice with 100ml. portions of ethyl acetate, washed three times with 75 ml. portionsof water, dried over magnesium sulphate and evaporated in a vacuum at40. (R)-oc-[4-(onitrophenylsulphenylaminomethyl) benzoyloxy] isocaproicacid was obtained as a resin which 'was reacted with a triethylaminesalt of 6-aminopenicillanic acid without further purification.

(B) The process:

7.0 g. of pivalic acid chloride were added dropwise with stirring at 15to 24.0 g. of(R)-u-[4-(o-nitrophenylsulphenylaminomethyl)-benzoyloxy]-isocaproic acidin ml. of tetrahydrofuran and 8 m1. of triethylamine. After 20 minutes,a cold (15) solution of 13 g. of 6-aminopenicillanic acid in 80 m1. ofchloroform and 16 ml. of triethylamine was added, the mixture wasstirred for 1 hour at 10 and for 20 hours at 25. The solvent wasdistilled ofi in a vacuum at 20, the residue suspended in 150 ml. ofethyl acetate, filtered from insolubles and the filtrate extracted with200 ml. of ice-water. The aqueous solution was adjusted to pH 0.5 with 3N sulphuric acid at and extracted with 300 ml. of ethyl acetate, washedthree times with a sodium chloride solution, dried over magnesiumsulphate and evaporated in a vacuum at 20. The residue was dissolved in400 ml. of ether, filtered and the filtrate mixed with 28 ml. of 2 N-sodium 2-ethylcaproate in ethyl acetate. The sodium salt of thepenicillin product was filtered ofi. by suction, washed with ether andpetroleum ether and dried.

34.0 g. of the foregoing sodium salt were dissolved in 300 ml. of waterand 300 ml. of dioxan and cooled to 0, 8.0 g. of thioacetamide wereadded with stirring and 96 ml. of 1 N hydrochloric acid were then addeddropwise over a period of minutes. The mixture was further stirred at 0.for 1.5 hours, the precipitate filtered oil, rinsed with 100 ml. ofwater and evaporated at and 0.1 torr to a volume of 500 ml. The solutionwas ex tracted with 200 ml. of ethyl acetate and the aqueous phaseadjusted to pH 4.2 with triethylarnine. The solution was evaporated to350 ml. at 20 and 0.1 torr, filtered .and thereafter further evaporatedto 60 ml. The penicillin product crystallized from this concentrate at0. It was suspended in 700 ml. of water, dissolved in 1 N hydrochloricacid at pH 2.0, filtered, adjusted to pH 4.2 with triethylamine,concentrated to 100 ml. at 20 and 0.1 torr and crystallized for 24 hoursat 0. There was obtained (R) 1'- [(4 aminoethylbenzoyloxy) 3methylbutylflpenicillin; [0;] +183 (c.=l.00 in a mixture of 50 vol.percent each of water and B-acetamic-butyric acid ethyl ester); meltingpoint from 200 (slow decomposition).

EXAMPLE 24 (R,S) l- (p-cyanobenzoyloxy) -butyl] -penicillin potassium(A)The preparation of the starting material:

A solution of 35.5 g. of (R,S)-u-bromo-valeric acid t-butyl ester, 29.4g. of p-cyanobenzoic acid and 20.2 g. of triethylamine in 300 ml. ofabsolute dimethylformamide was stirred at 25 for 20 hours and at 100 for2 hours and subsequently evaporated to dryness in a vacuum. The residuewas dissolved in a mixture of 350 ml.

of ethyl acetate and 150 ml. of water. The ethyl acetate phase waswashed with ice-cold 5% sodium bicarbonate solution and water, driedover magnesium sulphate and evaporated in a. vacuum. The residue wasdissolved in 400 ml. of low-boiling petroleum ether. After standing atl0 for 20 hours, the mixture was filtered and the filtrate evaporated ina vacuum. The residual (R,S)-a- (p-cyanobenzoyloxy)-valeric acid t-butylester was dissolved in 75 ml. of anhydrous trifluoroacetic acid. Thesolution was maintained at 25 for 30 minutes and then evaporated in avacuum. The residue was dissolved in 100 ml. of absolute benzene and thesolution evaporated to dryness in a vacuum. The(R,S)-a-(p-cyanobenzoyloxy)-valeric acid thus obtained wasrecrystallized from ethyl acetate/petroleum ether. Melting point 95 96.

(B) The process:

Starting from (R,S)-a-(p-cyanobenzoyloxy)-valeric acid produced aboveaccording to the procedure described in Example 4 there was obtained[(R,S)-l-(p-cyanobenzoyloxy)-butyl]-penicillin potassium of meltingpoint 157 (decomposition); [0:1 --198 (c.=1 in water).

EXAMPLE 25 (R,S) 1- (p-carbamoyl-benzoylox y) -pentyl] -penicillinpotassium (A) The preparation of the starting material:

A solution of 60.3 g. of (R,S)-u-bromo-caproic acid t-butyl ester, 43.3g. of terephthalamidic'acid and 26.5 g. of triethylamine in 400 ml. ofabsolute dimethylformamide was stirred at 25 for 20 hours and at 100 for2 hours and subsequently evaporated in a vacuum. The residue wasdissolved in a mixture of 500 ml. of ethyl acetate and 500 ml. of waterand separated ofi from a 24 little insoluble material. The ethyl acetatephase was washed with ice-cold 5% sodium bicarbonate solution and water,dried over magnesium sulphate and evaporated in a vacuum. The (R,S) 1x(p-carbamoylbenzoyloxy)- caproic acid t-butyl ester thus obtained wasdissolved in ml. of anhydrous trifiuoroacetic acid. The solution wasmaintained at 25 for 30 minutes and then evaporated in a vacuum. The(R,S)-ix-(p-carbamoylbenzoyloxy)-caproic acid thus obtained wasrecrystallized from methanol. Melting point 175 l77.

(B) The process:

Starting from (R,S -a- (pc arbamoylbenzoyloxy) -caproic acid producedabove according to the procedure described in Example 4 there wasobtained [(R,S)-l-(pcarbamoylbenzoyloxy)-pentyl]-penicillin potassium ofmelting point 169 (decomposition); [(11 +144 (c.= 1 in water.)

EXAMPLE 26 (R,S) 1- (p-hydroxy-benzoyloxy -3-methylbutyl] penicillinsodium (A) The preparation of the starting material:

14.0 g. of (R,S,)-a-bromo-isocaproic acid benzyl ester and 12.1 g. ofthe sodium salt of 4-tetrahydropyranyloxybonzoic acid were stirred for 3hours at in 100 ml. of dimethylformamide. The mixture was subsequentlycooled, diluted with water and extracted with high-boiling petroleumether. The petroleum ether solution was washed with dilute sodiumbicarbonate solution, washed with water, dried over sodium sulphate andevaporated in a vacuum. The residue was hydrogenated in methanol withthe addition of Pd/C. After removal of the catalyst, the solution wasevaporated in a vacuum. (R,S)a-(tetrahydropyranyloxy-benzoyloxy)-isocaproic acid was obtained as an oilyresidue (12.5 g.).

(B) The process:

Starting from (R,S)-u-(4-tetrahydropyranyloxybenzoyloxy)-isocaproic acidproduced above according to the procedure described in Example 18 therewas obtained [(R,S) 1 (phydroxy-benzoyloxy) 3 methylbutyl]- penicillinsodium of melting point 190 (decomposition); [111 +139 (c.=1 in water).

EXAMPLE 27 [(R)-l-(p-anisoyloxy)-3-methoxybutyl] -penicillin sodium (A)The preparation of the starting material:

26.0 g. of p-anisoyl chloride in 50 ml. of tetrahydrofuran were addeddropwise with stirring at 10 to a solution of 33.8 g. ofDw-hydroxy-isocaproic acid benzyl ester and 22.5 ml. of triethylamine inml. of tetrahydrofuran, stirred for an additional hour at 0 and at 25for 20 hours. The triethylamine hydrochloride was filtered 01?, thefiltrate evaporated in a vacuum at 40, the residue, in 250 ml. of ethylacetate, Washed with l N hydrochloric acid, water, 8% sodium bicarbonatesolution and water, dried over magnesium sulphate and evaporated in a.vacuum at 40. The resulting oil was dissolved in benzene andchromatographed on a column of 300 g. of kieselgel. After elution with750 ml. of benzene, the eluate was evaporated in a vacuum at 40.(R)-a-(p-anisoyloxy)-isocaproic acid benzyl ester was obtained as acolorless oil; [a] +5 (c. =4.5 in alcohol).

32.0 g. of (.R)-a-(p-anisoyloxy)-isocaproic acid benzyl ester werehydrogenated in 200 ml. of alcohol with pal ladium-charcoal. Thecatalyst was filtered oif and the filtrate evaporated in a vacuum at 40.The oil thus obtained was dissolved in excess 8% sodium bicarbonatesolution, Washed with ether, the aqueous phase adjusted to pH 2 withconcentrated hydrochloric acid and extracted-with 200 ml. of ether,washed with water, dried over magnesium sulphate and evaporated in avacuum. (R)-a-(p-anisoyloxy)-isocaproic acid was obtained as a colorlessoil; [0;]; +2.4 (c.=4.0 in alcohol).

35.8 g. of the foregoing acid were boiled at reflux for 3 hours in 100ml. of benzene and 30 ml. of thionyl chloride, evaporated in a vacuum at45 and evaporated twice with 50 ml. portions of benzene and dried. Theoily (R)-u-(p-anisoyloxy)-isocaproic acid chloride thus obtained wasimmediately reacted with the triethylammonium salt of6-aminopenicillanic acid.

(B) The process:

Starting from (R)-a-(p-anisoyloxy)-isocaproic acid chloride according tothe procedure described in Example 1 there was obtained[(R)-1-(p-anisoyloxy)-3-methoxybutyl]-penicillin sodium; [th, l86(c.'=l.00 in Water); melting point 187-190 (decomposition).

EXAMPLE 28 [(R,S -1- (p-anisoyloxy -propyl] -penicillin potassium (A)The preparation of the starting material:

A solution of 30.4 g. of p-anisic acid, 51.4 g. of (R,S)-a-bromo-butyric acid benzyl ester and 22.3 g. of triethylamine wereboiled under reflux for 20 hours in 400 ml. of absolute dioxan. Aftercooling, the triethylamine hydrobromide was filtered off by suction andthe filtrate evaporated in a vacuum. The residue was taken up in 500 m1.of ethyl acetate. The ethyl acetate solution was washed with water,ice-cold sodium bicarbonate solution and water, dried over magnesiumsulphate and evaporated in a vacuum. The residual(R,S)-a(p-anisoyloxy)-butyric acid benzyl ester was distilled in a highvacuum; boiling point 187-l88/0.5 mm. Hg.

29.5 g. of (R,S)-a-p-anisoyloxy)-butyric acid benzyl ester weredissolved in 650 ml. of alcohol and, with the addition of Pd/C,hydrogenated up to the uptake of the theoretical amoint of hydrogen. Thecatalyst was separated ofi, the filtrate evaporated in a vacuum and theresidue dissolved in 500 ml. of ethyl acetate. The ethyl acetatesolution was washed with water and extracted twice with 150 ml. portionsof 5% sodium bicarbonate solution. The alkaline solution was cooled withice, made congo-acidic with concentrated hydrochloric acid and extractedwith 450 ml. of ethyl acetate. The ethyl acetate solution was washedwith water, dried over magnesium sulphate and evaporated in a vacuum.The (R,S)-a-panisoyloxy)-butyric acid thus obtained was recrystallizedfrom cyclohexane. Melting point 79 80.

(B) The process:

Starting from (R,S)-m-(p-anisoyloxy)-butyric acid according to theprocedure described in Example 4 there was obtained[(R,S)-1-(p-anisoyloxy)-propyl]-penicillin potassium of melting point175 (decomposition); [041 +2l1 (c.-=1 in water).

EXAMPLE 29 (R) l- (o-anisoyloxy) -2-methylpropyl] -penicillin potassium(A) The preparation of the starting material:

17.1 g. of o-anisoylchloride in 50 ml. of ether were added dropwise withstirring to a cold (-15) solution of 11.8 g. of D-a-hydroxy-isovalericacid in 50 ml. of pyridine. The mixture was stirred at -15 for 2 hours.The pyridine was distilled off in a vacuum at 45. The residue wasdissolved in excess ice-cold 3 N hydrochloric acid, extracted with 150ml. of ethyl acetate, washed with 3 N hydrochloric acid, extracted with150 ml. of ethyl acetate, washed with 3 N hydrochloric acid and waterand the ethyl acetate repeatedly extracted with 8% sodium bicarbonatesolution. The combined sodium bicarbonate so lutions adjusted to pH 2with concentrated hydrochloric acid and extracted with benzene. Thebenzene solution was washed with water, dried over magnesium sulphateand evaporated in a vacuum. (R)-a-(oanisoyloxy)-isovaleric acid wasobtained as a colorless oil.

(B) The process:

Starting from (R)-u-(o-anisoyloxy)-isovaleric acid obtained above andaccording to the procedure described in Example 4 there was obtained[(R)-l-(o-anisoyloxy)-2- methylpropyl]penicillin potassium salt. [(11+180 (c.=1.00 in water); melting point from 150' (slow decomposition).

EXAMPLE 30 (R) -3-methyl-1- veratroyloxy) -butyl] -penicillin sodium (A)The preparation of the starting material:

18.3 g. of veratroyl chloride in 40 ml. of tetrahydrofuran were addeddropwise at 10 with stirring to a solution of 20.2 g. ofD-u-hydroxy-isocaproic acid benzyl ester and 12.7 ml. of triethylaminein ml. of tetrahydrofuran, stirred at 0 for 1 hour and at 25 for 20hours. The triethylamine hydrochloride was filtered off, the filtrateevaporated in a vacuum at 40. The resulting oil in 200 ml. of ethylacetate, was washed with 1 N hydrochloric acid, water, 8% sodiumbicarbonate solution and water, dried over magnesium sulphate andevaporated in a vacuum at 40. The resulting oil was chromatographed on acolumn of 300.0 g. of kieselgel 3070 mesh ASTM in benzene. After elutionwith 700 ml. of benzene, the eluate was evaporated in a vacuum.(R)-a-veratroyloxyisocaproic acid benzyl ester was obtained as acolorless oil which was hydrogenated in 200 ml. of alcohol with 5%palladium-charcoal. The catalyst was filtered 01f, the filtrateevaporated in a vacuum at 45 the residue dissolved in excess bicarbonatesolution, extracted with ether, the aqueous phase adjusted to pH 2 withconcentrated hydrochloric acid, extracted twice with 100 ml. portions ofether, washed with water, dried over magnesium sulphate and evaporatedin a vacuum. (R)-a-veratroyloxyisocaproic acid was thus obtained as acolorless oil.

12.5 g. of the foregoing acid were boiled at reflux in 50 ml. of benzeneand 15 ml. of thionyl chloride for 2 hours, evaporated in a vacuum at45, evaporated twice with 20 ml. portions of benzene and dried in avacuum at 45. (R)-u-veratroyloxy-isocaproic acid chloride was obtainedas an oil which was immediately reacted with the triethylammonium saltof fi-aminopenicillanic acid.

(B) The process:

Starting from (R)-a-veratroyloxy-isocaproic acid chloride in accordancewith the procedure described in Example 1 there was obtained[(R)-3-methyl-1-(veratroyloxy)- butyl]penicillin sodium salt; '+160(c.=1 in water); melting point from (slow decomposition).

EXAMPLE 31 (R)-3-methyl-1-(3,4,S-trimethoxy-benzoyloxy) -butyl]-penicillin sodium (A) The preparation of the starting material:

24.1 g. of 3,4,5-trimethoxybenzoyl chloride in 50 ml. of chloroform wereadded dropwise with stirring to a cold 15) solution of 13.2 g. ofD-u-hydroxy-isocaproic acid in 70 ml. of pyridine. The mixture wasstirred at 10 for 2 hours and at 20 for 20 hours. The pyridine wasdistilled off in a vacuum at 45. The residue was dissolved in excessice-cold 3 N hydrochloric acid, extracted with 200 ml. of ethyl acetate,washed with 3 N hydrochloric acid and water and the ethyl acetaterepeatedly extracted with 8% sodium bicarbonate solution. The combinedsodium bicarbonate solutions were rinsed with ethyl acetate, adjusted topH 2 with concentrated hydrochloric acid and extracted with ml. of ethylacetate. The

ethyl acetate solution was washed four times with 50 ml.

portions of water, dried over magnesium sulphate and evaporated in avacuum at 40. The residue was suspended in 50 ml. of ice-cold ether,filtered off in a vacuum and the filtrate evaporated in a vacuum. Theoil obtained was dissolved in a mixture of 40 ml. each of ether andpetroleum ether and, after 1 hour, filtered off from a further smallamount of crystals. From the filtrate, by evaporation in a vacuum(R)-a-(3,4,5-trimethoxybenzoyloxy)-isocaproic acid was obtained as acolorless honey. 150 g. of this acid were boiled at reflux for 2 hoursin 50 ml. of benzene and 15 ml. of thionyl chloride, evaporated in a 27vacuum at 45 evaporatedtwice with 30 ml; portions of benzene and driedin a vacuum at 45. The (Rye-(3,4,5- trimethoxybenzoyloxy)isocaproic acidchloride thus obtained was immediately reacted with the triethylammoniumsalt of G-aminopenicillanic acid.

(B) The process:

Starting from (R)-u-(3,4,5-trimethoxybenzoyloxy)-isocaproic acidchloride thus obtained and according to the procedure described inExample 1 there was obtained [(R) 3methyl-1-(3,4,S-trimethoxybenzoyloxy)-butyl]- penicillin sodium salt; M11+l56 (c.=1.00 in water); melting point from 140 (slow decomposition).

EXAMPLE 32 (R,S)1-(piperonyloyloxy)pentyl] penicillin potassium (A) Thepreparation of the starting material:

A solution of 35.1 g. of (R,S)'-a-bromo-caproic acid t-butyl ester, 24.9g. of piperonylic acid and 15.9 g. of triethylamine in 250 ml. ofabsolute dimethylformamide was stirred at 25 for 20 hours and at 100 for2 hours and subsequently evaporated to dryness in a'vacuum. The residuewas dissolved in a mixture of 400 ml. of ethyl acetate and 150 ml. ofwater. The ethyl acetate phase was then washed with ice-cold 5% sodiumbicarbonate solution and water, dried over magnesium sulphate andevaporated in a vacuum. The (R,S)-u-piperony1oyloxycaproic acid t-butylester thus obtained was dissolved in 60 ml. of anhydrous trilluoroaceticacid. The solution was maintained at 25 for 2 hours and then evaporatedto dryness in a vacuum. The residue was dissolved in 100 ml. of absolutebenzene and the solution evaporated to dryness in a vacuum. The residuewas dissolved in 350 ml. of ethyl acetate. The ethyl acetate solutionwas washed with 150 ml. of water and then extracted with three 150 m1.portions of 5% sodium bicarbonate solution. The alkaline solution wasmade congo-acidic with 3 N hydrochloric acid and extracted with 400 ml.of ethyl acetate. The ethyl acetate solution was washed with water,dried over magnesium sulphate and evaporated to dryness in a vacuum. The(R,S)-u-piperonyloyloxycaproic acid thus obtained was recrystallizedfrom cyclohexane. Melting point 66-67.

(B) The process:

Starting from (R,S)-u-piperonyloyloxy-caproic acid according to theprocedure described in Example 4 there EXAMPLE 33[(R)1-(p-aminobenzoyloxy)-3-methylbuty1]penicillin sodium (A) Thepreparation of the starting material:

22.0 g. of (R)-a-(p-nitrobenzoyloxy)isocaproic acid benzyl ester(obtained in accordance with Example 34, Part (A) were hydrogenated in400 ml. of alcohol with 5% palladium-charcoal. The catalyst was filtered011?, the filtrate evaporated in a vacuum at 40 and the residuecrystallized from benzene. There was thus obtained (R)-u-(p-aminebenzoyloxy)isocaproic acid of melting point 15l153; [:1 7.6(c.-=2.00 in methanol).

25.0 g. of (R)m-(p-aminobenzoyloxy)isocaproic acid and 12.0 g. ofN-hydroxy-succinimide were dissolved in 500 ml. of acetonitrile, treatedwith 21.0 g. of dicyclohexylcarbodiimide and stirred at 20 for 3 hours,The dicyclohexylurea was filtered oil and the filtrate evaporated in avacuum at 40. The residue, dissolved in 200 ml. of ethyl acetate, waswashed with sodium bicarbonate and water. There was obtained, afterdrying over magnesium sulphate and evaporation in a vacuum at 40,(R)a-(p-a'minobenztrybxy)isocaproic acid N- hydroxy-succinimide ester asa resin which was employed 28 for the reaction with the triethylammoniumsalt of 6- aminopenicillanic acid without further purification.

(B) The process: 13.0 g. of d-aminopenicillanic acid in ml. ofchloroform and 16 ml. of triethylamine were combined with 20.0 g. of(R)-oc- (p-aminobenzoyloxy)isocaproic acid N- hydroxysuccinimide esterin 50 ml. of chloroform maintained at 25 for 24 hours and thenevaporated in a vacuum at 25. The residue was dissolved in 200 ml. ofice-water, washed three times with 50 ml. portions of ethyl acetate,adjusted to pH 2.5 with 3 N sulphuric acid at 0 and extracted with 400ml. of ethyl acetate. The ethyl solution was washed three times withwater, dried over magnesium sulphate, evaporated in a vacuum to a volumeof 100 ml. and treated with 20 ml. of a 2 N solution of sodium2-ethylcaproate in ethyl acetate. After 1 hour, the sodium salt wasfiltered off, washed with ethyl acetate ether and petroleum ether anddried at 20. There was thus obtained[(R)l-(p-aminobenzoyloxy)3-methylbutyl ]-penicillin sodium salt; +1323(0.:1 in water); melting point from 205 (slow decomposition).

EXAMPLE 34 [(R-)-3-methyl-l-(p-nitrobenzoyloxy)-butyl]penicillin sodium(A) The preparation of the starting material:

37.2 g. of p-nitrobenzoyl chloride in ml. of tetrahydrofuran were addeddropwise at 15 with stirring over a period of 30 minutes to a solutionof 44.5 g. of D-a-hydroxy-isocaproic acid benzyl ester and 28 ml. oftriethylamine in 300' ml. of tetrahydrofuran and stirred at 0 for 2hours and at 25 for 20 hours. The triethylamine hydrochloride wasfiltered off, the filtrate evaporated in a vacuum at 40 and the residue,in ethyl acetate, washed neutral with l N hydrochloric acid, water, 8%sodium bicarbonate and water. After drying over magnesium sulphate, theethyl acetate was distilled off and the resulting oil crystallized from25 ml. of alcohol at 25. The (R)-oc-(p-nitrobenzoyloxy)isocaproic acidbenzyl ester thus obtained, melting point 48-49, [M +11.5 (c.=3 inalcohol), was dissolved in 70 ml. of glacial acetic acid, treated with70 ml. of glacial acetic acid, treated with 70 ml. of 33% hydrobromicacid in glacial acetic acid, evaporated in a vacuum at 45 after 20 hoursand the oil obtained dissolved in excess 8% sodium bicarbonate solution,extracted three times with 100 ml. portions of ether and the aqueousphase adjusted to pH 2 with concentrated hydrochloric acid. The acid wasthen extracted with ether, washed with water, dried over magnesiumsulphate, strongly concentrated in a vacuum and crystallized by additionof petroleum ether. There was thus obtained(R)-a-(p-nitrobenzoyloxy)isocaproie acid of melting point 79-81; [041+l1.9 (c.=4.00 in alcohol).

16.0 g. of the foregoing acid are boiled at reflux for 2 hours in 80 ml.of benzene with 20 ml. of thionyl chloride, evaporated in a vacuum at45, evaporated twice with 30 ml. portions of benzene and dried in avacuum at 45 The oily (R)-a-(p-nitrobenzoyloxy)isocaproic acid chloridethus obtained was immediately reacted with the trimethylammonium salt of6-aminopenicillanic acid.

(B) The process:

Starting from (R)a-(p-nitrobenzoyloxy)isocaproic acid according to theprocedure described in Example 1 there was obtained[(R)3-rnethyl-1-(p-nitrobenzoyloxy)- butyl]-penicillin sodium salt;[(11, +187 (c.'=1.00 in water), melting point from 180 (decomposition).

EXAMPLE 35 (R) 1 (p-ethoxyacetamido-benzoyloxy) 3-methylbutyl]penicillin sodium (A) The preparation of the starting material: 20.0 g.of p-aminobenzoic acid methyl ester and 13.7 g. of ethoxyacetic acid in200 ml. of acetonitrile were treated 29 at with 27.2 g. ofdicyclohexylcarbodiimide in 0 ml. of acetonitrile and left to stand at25 for 3 hours. The dicyclohexylurea was filtered oif, the filtrateevaporated in a vacuum at 40, the residue dissolved in 200ml. of ethylacetate, washed with 3 N hydrochloric acid,

water, 8% sodium bicarbonate solution and water, dried over magnesiumsulphate and evaporated in a vacuum at 40. By crystallization from ethylacetate/petroleum ether, there was obtained p-ethoxyacetamidobenzoicacid methyl ester of melting point 8385.

21.5 g. of p-ethoxyacetamidobenzoic acid methyl ester were dissolved in200 ml. of methanol and saponified at 25 for 24 hours with.4.0 g. ofsodium hydroxide in ml. of water. The solution was evaporated in avacuum at 40, the residue dissolved in 150 ml. of water, washed twicewith 50 ml. of ether each time, adjusted to pH 2 with concentratedhydrochloric acid, extracted twice with 100 ml. portions of ethylacetate, dried over magnesium sulphate, evaporated in a vacuum at 40 andcrystallized from ethyl acetate/petroleum ether. There was thus obtainedp-ethoxyacetamidobenzoic acid of melting point 175 -177 13.0 g. ofp-ethoxyacetamidobenzoic acid were boiled under reflux for 1.5 hours in50 ml. of benzene and ml. of thionyl chloride, evaporated in a vacuum at40, evaporated twice with 20 ml. portions of benzene and dried. 14.5 g.of this acid chloride were dissolved in ml. of tetrahydrofuran and, withstirring, added dropwise at 10" to a solution of 14.1 g. ofD-a-hydroxy-isocaproic acid benzyl ester in 150 ml. of tetrahydrofuranand 8.9 ml. of triethylamine. After 1 hour at 5 and 20 hours at 25, thetriethylamine hydrochloride was filtered oif, the filtrate evaporated ina vacuum at the residue, in 150 ml. of ethyl acetate, washed 1 Nhydrochloric acid, water, 8% sodium bicarbonate solution and water,dried over magnesium sulphate and evaporated in a vacuum.(R)-u-(p-ethoxyacetamidobenzolyloxy)-isocaproic acid benzyl ester wasobtained as an oil which was hydrogenated in 300 ml. of alcohol with 5%palladium-charcoal. The catalyst was filtered .off and the filtrateevaporated in a vacuum at .40. The residue was dissolved in excesssodium bicarbonate solution, extracted twice with ml. portions of ether,adjusted to pH with concentrated hydrochloric acid and extracted twicewith 80 ml. portions of ethyl acetate. The ethyl acetate solution waswashed with water, dried over magnesium sulphate and evaporated in avacuum. (R)-a-(pethoxyacetamidobenzoyloxy)-isocaproic acid was obtainedas an oil.

16.6 g. of the foregoing acid was boiled at reflux for 2 hours in 50 ml.of benzene and 12 ml. of thionyl chloride evaporated in a vacuum at 45and thereafter evaporated twice with 30 ml. portions of absolutebenzene. (R)- a-(p ethoxy acetamidobenzoyloxy) isocaproicacid chloridewas obtained as an oil which was immediately reacted with thetriethylammonium salt of 6-aminopeni-' cillanic acid.

(B) The process:

Starting from (R)-u (p-ethoxyacetamidobenzoyloxy)- isocaproic acidchloride according to the procedure described in Example 1 there wasobtained [(R)-1-(p-ethoxyacetamidobenzoyloxy)3-methylbutyl] penicillinsodium salt; +160 (c.=1 in watenmelting point from 205 (decomposition).

EXAMPLE 36 80 m1. of ether and a solution of 18.0 g. of sodium hydoxidein 100 ml. of water were simultaneously added dropwise with stirringwithin 45 minutes'toa cold (0) solution of'41.0 g.otp-aminoben'zoic acid in 200 ml. of

water and 18.0 g. of sodium hydroxide. The mixture was stirred at 0 for1 hour and at 20 for 20 hours. The suspension was extracted twice with100 ml. portions of ether. The slightly alkaline aqueous solution wasadjusted topI-I 1 with concentrated hydrochloric acid and extractedthree times with 200 ml. portions of ethyl acetate. The ethyl acetatesolution was washed with 3 N hydrochloric acid and water, dried overmagnesium sulphate and crystallized by evaporation in a vacuum at 40.p-Methanesulfonylamido-benzoic acid of melting point 230232 (decomposition) was thus obtained. This acid was dissolved in thecalculated amount of 1 N caustic soda, evaporated in a vacuum and theresulting sodium salt dried in a vacuum at 28.4 g. of the sodium salt ofp-methanesulfonylamidobenzoic acid were introduced with stirring into asolution of 28.5 g. of DL-a-bromo-isocaproic acid benzyl ester in 300ml. of dimethylformamide. The suspension was heated to for 20 hours. Thediethylformamide was distilled 0E in a vacuum at 60 and the residue, in300 ml. of ethyl acetate was washed with 3 N hydrochloric acid, water,8% sodium bicarbonate and water, evaporated in a vacuum at 45 and dried.(R,S)a-(p-methanesulfonylamidobenzoyloxy)-isocaproic acid benzyl esterwas obtained as an oil which was hydrogenated in 200 ml. of alcohol with5% palladium-charcoal. The catalyst was filtered 01f, the filtrateevaporated in a vacuum at 45 the residue dissolved in excess 8% sodiumbicarbonate solution and extracted with ether. The sodium bicarbonatesolution was then adjusted to pH 2 with concentrated hydrochloric acid,extracted with ethyl acetate, washed with water,

dried over magnesium sulphate and evaporated in a vacu- 'oxy)-isocaproicacid chloride according to the procedure described inExample 1 there wasobtained [(R,S)-l-(p- :methanesulfonylamidobenzoyloxy) 3 methylbutyl]-penicillin sodium salt; +166.5 (c.:=1.00 in water); melting point from196 (decomposition).

EXAMPLE 37 [(R,'S)- l-(p-pyrrol-l-yl-benzoyloxy) -butyl]- penicillinpotassium (A) The preparation of the starting material: A solution of54.2 g. of (R,S)-a-bromo-valeric acid benzyl ester, 28.1 g. of p(pyrrol-1-yl)-benzoic acid and 15.2 g. of triethylamine in 200 ml. ofabsolute dimethylformarnide was stirred at 25 for 20 hours and at 100for 3 hours and subsequently evaporated to dryness in a vacuum. Theresidue was dissolved in a mixture of 400 ml. of ethyl acetate and 250ml. of water. The ethyl acetate phase was washed with ice-cold 5% sodiumbicarbonate solution and water, dried over magnesium sulphate andevaporated in a vacuum. The (R,S)-a-(p-pyrrol-l-yl-benzoyloxy)valericacid benzyl ester thus ob tained was dissolved in 1 liter of alcoholand, with the addition of Pd/ C, hydrogenated until cessation ofhydrogen uptake. The catalyst was separated off and the filtrateevaporated in a vacuum. The (R,S) a (p-pyrrol-1-benzoyloxy)-valeric acidwhich was obtained in crystalline form was recrystallized from benzene.Melting point 133+134.

EXAMPLE 3 8 (A) The preparation of the starting material):

3.19 g. of (R)-u-hydroxy-isocaproic acid and 6.77 ml.

of triethylamine were dissolved in 50 ml. of absolute tetrahydrofuranand cooled to With stirring, a solution of 4.5 g. of4-methylmercaptobenzoyl chloride in 30 ml. of absolute tetrahydrofuranwas added dropwise. The mixture was then stirred at room temperature for4.5 hours and then concentrated in a vacuum. The residue was dissolvedin water, the aqueous solution made acidic with dilute hydrochloric acidand the acid extracted with ethyl acetate. After washing with water, theethyl acetate extract was dried over sodium sulphate and concentrated ina vacuum. The residue was taken up in high-boiling petroleum ether, asmall amount of undissolved material was separated off and the petroleumether was evaporated in a vacuum. (R) a(4-methylmercaptobenzoyloxy)-isocaproic acid was obtained as an oilyresidue (6.9 g.).

(B) The process:

Starting from (R)-a-(4-methylmercaptobenzoyloxy)- isocaproic acidaccording to the procedure described in Example 18 there was obtained[:(R)-3-methyl-1-(pmethylthiobenzoyloxy)-butyl]-penicillin sodium ofmelting point 156 (decomposition); [@1 +176 (cl-:1 in water).

EXAMPLE 39 (R,S) -1-(p-methylsulfenyl-benzoyloxy) -butyl] penicillinpotassium (A) The preparation of the starting material:

A solution of 28.5 g. of (R,S)-a-bromo-valeric acid tbutyl ester, 26.3g. of o-methylsulfonylbenzoic acid and 13.3 g. of triethylamine in 200ml. of absolute dimethylformamide was stirred at 25 for 20 hours and at100 for 2 hours and subsequently evaporated in a vacuum. The residue wasdissolved in a mixture of "500 ml. of ethyl acetate and 250 m. of water.The ethyl acetate phase was washed with ice-cold 5% sodium bicarbonatesolution and water, dried over magnesium sulphate and evaporated in avacuum. The (R,S)-a-(p-methylsulfonylbenzoyloxy)- valeric acid t-butylester thus obtained was recrystallized from cyclohexane. Melting point85 86.

A solution of 33.6 g. (R,S)-a-(p-methylsulfonylbenzoyloxy)-valeric acid6-butyl ester in 50 ml. of anhydrous trifiuoroacetic acid was maintainedat for minutes and then evaporated in a vacuum. The residue wasdissolved in 50 ml. of absolute benzene and the solution evaporated in avacuum. The (R,S)-a-(p-methylsulfonylbenzoyloxy)-valeric acid thusobtained was recrystallized from benzene. Melting point 118120.

(B) The process:

Starting from (R,S)-ot-(p-methylsulfonylbenzoyloxy)- valeric acidaccording to the procedure described in Example 4 there was obtained[(R,S)-1-(p-methy1sulfonylbenzoyloxy-butyl]-penicillin potassium ofmelting point 130 (decomposition); +172 (c.=1 in water).

EXAMPLE 40 (R,S)-1-(p-sulfamoyl-benzoyloxy) -pentyl]- penicillinpotassium (A) The preparation of the starting material:

A solution of 30.2 g. of (R,S)-a-bromo-caproic acid t-butyl ester, 26.3g. of p-sulfamoyl benzoic acid and 13.3 g. of triethylamine in 200 ml.of absolute dimethylformamide was stirred at 25 for 20 hours and at 100for 2 hours and subsequently evaporated to dryness in a vacuum. Theresidue was dissolved in a mixture of 500' ml.

of ethyl acetate and 250 ml. of water. The ethyl acetate phase waswashed with ice-cold 5% sodium bicarbonate solution and water, driedover magnesium sulphate and evaporated in a vacuum. The(R,S)-a-(p-sulfamoylben zoyl0xy)-caproic acid t-butyl ester thusobtained was recrystallized from cycloheXane/low-boiling petroleumether. Melting point 8789.

37.6 g. of (R,S)-a-(p-sulfamoylbenzoyloxy)-caproic acid t-butyl esterwere dissolved in 50 ml. of anhydrous trifluoroacetic acid. The solutionwas maintained at 25 for 30 minutes and then evaporated in a vacuum. Theresidue was dissolved in 50 ml. of absolute benzene and the solutionevaporated to dryness in a vacuum. The(R,S)-a-(p-sulfan1oylbenzoyloxy)-caproic acid thus obtained wasrecrystallized from ethyl acetate/low-boiling petroleum ether. Meltingpoint 118-124.

(B) The process:

I Starting from (R,S)- x-(p-sulfamoylbenzoyloxy)-caproic acid accordingto the procedure described in Example 4 there was obtained(R,S)-1-(p-sulfamoylbenzoyloxy)- pentylJ-penicillin potassium of meltingpoint 190 (de composition); [M +126 (c.=1 in water). 7

EXAMPLE 41 [(R,S) -1- (p-sulfamoyl-benzoyloxy) -hexyl] penicillinpotassium (A) The preparation of the starting material:

A solution of 37.1 g. of (R,S)-a-bromo-heptylic acid t-butyi ester, 30.0g. of p-sulphamoylbenzoic acid and 15.2 g. of triethylamine in 200 ml.of absolute dimethylformamide was stirred at 25 for 18 hours and at for2 hours and subsequently evaporated in a vacuum. The residue wasdissolved in a mixture of 400 ml. of ethyl acetate and ml. of water. Theethyl acetate phase was washed with ice-cold 5% sodium bicarbonatesolution and water, dried over magnesium sulphate and evaporated in avacuum. The (R,S)-a-(p-sulfamoy1benzoyloxy)-heptylic acid t-butyl esterwas dissolved in 50 ml. of anhydrous trifluoroacetic acid. The solutionwas maintained at 25 for 45 minutes and then evaporated in a vacuum. Theresidue was dissolved in 100 m1. of absolute benzene and the solutionevaporated in a vacuum. The (R,S)-a-(p-sulfamoylbenzoyloxy)-heptylicacid thus obtained was recrystallized from benzene. Melting point133135.

(B) The process:

Starting from (R,S)-a-(p-sulfamoylbenzoyloxy)heptylic acid according tothe procedure described in Example-4 there was obtained[(R,S)-l-(p-sulfamoylbenzoyl oxy)-hexyl]-penicillin potassium of meltingpoint (decomposition); [411 --|-131 (c.=1 in water).

EXAMPLE 42 The following composition was prepared as follows and filledinto gelatin capsules.

The penicillin was homogeneously blended with the microcrystallinecellulose and starch and compressed into slugs. The slugs were thenpassed through a suitable sieving machine and, after blending with thetalc and magnesium stearate, filled into suitable gelatin capsules.

33 EXAMPLE 4;

Reconstitutable injectable preparations were prepared as follows. Asolution containing 0.8 mg. ethyl p-hydroxybenzoate and 0.1 propylp-hydroxybenzoate per ml. was prepared by dissolving the substances inboiling hot water for injection. The solution was cooled and 288 g. (R)(p-chlorobenzoyloxy) -3-methylbutyl]-penicillin sodium were dissolvedina 1300 ml. portion thereof. The volume was then adjusted to 1500 ml. byaddition of the required amount of the solution. The final solution wassterilized by sterile filtration and filled aseptically into ml.ampules, each such ampules receiving 1.5 ml. The solutions were thenlyophilized and the ampules hermetically sealed.

What is claimed is:

1. Compounds represented by the formula wherein X is hydrogen, halogen,C -C alkyl, C -C alkoxy, C C alkylthio, (C -C alkanoyloxy)-methyl, (C Calkoxy)-methyl, C C -alkoxy-acetamido, hydroxy- (C1-C3 aminO-(C Cdi'(C1C3 amino, C -C alkylsulfonamido, C -C alkylsulfonyl, sulfamoyl,carbamoyl, amino, nitro, phenyl, trifluoromethyl, cyano, pyrrol-l-yl orhydroxy or two X symbols on adjacent carbon atoms together are a C .Calkylenedioxy; n is a whole number from 1 to 3 and T is a straight orbranched chain C -C alkyl or alkenyl radical, and

pharmaceutically acceptable salts and hydrated forms thereof.

2. Compounds in accordance with claim 1 wherein n is 1, X is in the 3 or4 position and is selected from the group consisting of chlorine,bromine and methoxy.

3. Compound in accordance with claim 1 wherein n is 2, X is in the 3 and4 position and is selected from the group consisting of chlorine,bromine and methoxy.

4. A compound in accordance with claim 1 wherein n is 1, X is 4-chloroand T is isobutyl, i.e., the compound [(R) 1 (4 chlorobenzoyloxy) 3methylbutyl1- penicillin.

5. A compound in accordance with claim 1 wherein n is 2, each X ischloro and said chloro substituents are in the 3 and 4 positions and Tis isobutyl, i.e., the compound [(R) 1 (3,4 dichlorobenzoyloxy) 3methylbutyH- penicillin.

6. A compound in accordance with claim 1 wherein n is 1, X is 4-chloroand T is isobutyl, i.e., the compound 34 [(R,S) 1 (4 chlorobenzoyloxy) 3methy1buty1]- penicillin.

7. A compound in accordance with claim 1 wherein n is 1, X is 4-fiuoroand T is isobutyl, i.e., the compounds [(R,S) 1 (4 fluorobenzoyloxy) 3methylbutyl]- penicillin.

8. A compound in accordance with claim 1 wherein n is 1, X is 4-fluoroand T is isobutyl, i.e., the compound [(R,S) 1 (3 bromobenzoyloxy)pentyl]-penicillin.

9. A compound in accordance with claim 1 wherein n is 1, X is 2-chloroand T is nbutyl, i.e., the compound [(R,S) 1 (2 chlorobenzoyloxy)pentyl] penicillin.

10. A compound in accordance with claim 1 wherein n is 1, X is4-methoxymethyl and T is isobutyl, i.e., the compound [(R) 1 (4methoxymethyl-benzoyloxy)-3- methy1butyl1-penicillin.

11. A compound in accordance with claim 1 wherein n is 1, X is4-acetoxymethyl and T is isobutyl, i.e., the compound [(R) 1 (4acetoxymethyl benzoyloxy)-3- methylbutyl]-penicillin.

12. A compound in accordance with claim 1 wherein n is 1, X is 4-phenyland T is isobutyl, i.e., the compound [(R) 1 (4 phenyl benzoyloxy) 3methylbutyl]- penicillin.

13. A compound in accordance with claim 1 wherein n is 1, X is 4-methoxyand T is isobutyl, i.e., the compound [(R) 1 (4 anisoyloxy) 3methylbutyl]-penicillin.

14. A compound in accordance with claim 1 wherein n is 3, each X ismethoxy and X substituents are in the 3, '4 and 5 positions and T isisobutyl, i.e., the compound [(R) 1 (3,4,5 trimethoxy benzoyloxy) 3methylbutyl]-penicillin.

15. A compound in accordance with claim 1 wherein n is 1, X is 4-nitroand T is isobutyl), i.e., the compound (R) -1- (4-nitrobenzoyloxy-3-methylbutyl] -penicillin.

16. A compound in accordance with claim 1 wherein n is 1, X is 4methylthio and T is isobutyl, i.e., the compound [(R) 1 (4 methylthi'obenzoyloxy)-3-methylbutyl]-penicillin.

References Cited UNITED STATES PATENTS 3,301,849 1/1967 Gottstein et al.260239.1 3,657,224 4/ 1972 Heuser 260-2391 3,678,032 7/1972 McCaully260239.l 3,681,342 8/1972 Butler et al. 260-239.]

NICHOLAS S. RIZZO, Primary Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N0.3.803.128 Dated April 9, 1974 Inventor(s) Furlem'neier eLal.

It is eertified that error appears inthe aboveidentified patent and thatsaid Letters Patent are hereby corrected as shown below:

Colfimn 33,, line 24 claim 1 (C -C alkanoylexy) methyl," should be (C -Qalkanoyloxywmethyl.)

Column 34, line 8 claim '8 "4-f1uor0 and 1" isobufiyl,"

should be 4=-bromo and '1" is n-b'utyl,

' Signed and sealed this 19th day of November 1974o (SEAL) Attest: I

MCCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents um Po-ws'o uo-ss) USCOMM-DC 603766 69 1 0.5. Govsflpmsm FRINYINGOFYICC nu o-us-:J4.

